Disclosure of Invention
The invention aims to solve the technical problems that: the device and the method for manufacturing the barrier in the polluted site are provided, so that the mixing efficiency of the gel material and the in-situ soil is improved, and the homogeneity of the barrier is improved.
In order to solve the technical problems, the embodiment of the invention adopts the following technical scheme:
In a first aspect, an embodiment of the present invention provides a manufacturing apparatus for a contaminated site barrier, including a walking base, a vibrating traction arm, and a stirring assembly, where the vibrating traction arm is connected to the walking base through a rotation driving assembly, and the stirring assembly is connected to the vibrating traction arm through a vibration driving assembly; the vibration type traction arm can drive the stirring assembly to rotate relative to the walking base, and the stirring assembly can vibrate relative to the vibration type traction arm along the axial direction of the stirring assembly.
As a further improvement of the embodiment of the invention, the stirring assembly comprises a stirring arm and a stirring cutter, wherein the stirring arm is arranged on the vibration type traction arm through the vibration driving assembly, and the stirring cutter is arranged on the stirring arm; the stirring cutter comprises a power wheel, a guide wheel, a bracket, a chain, stirring blades and a stirring driving piece; the bracket is fixedly connected with the stirring arm; the power wheel and the guide wheel are respectively arranged at two ends of the bracket, and the chain is sleeved on the power wheel and the guide wheel; the stirring driving piece is connected with the power wheel and is used for driving the power wheel to rotate; the stirring blade is fixedly connected to the chain.
As a further improvement of the embodiment of the invention, the stirring component is in sliding connection with the vibration type traction arm; the vibration driving assembly comprises two motors which rotate in opposite directions and two power shafts, and the two motors are arranged on the vibration type traction arm; one end of each power shaft is connected with the two motors, and the other end of each power shaft is connected with the two oval limiting holes on the stirring assembly.
As a further improvement of the embodiment of the invention, the stirring device further comprises a first discharging pipe and a second discharging pipe, wherein the first discharging pipe and the second discharging pipe are fixed on the stirring assembly.
In a second aspect, an embodiment of the present invention further provides a method for manufacturing a contaminated site barrier, where the apparatus for manufacturing a contaminated site barrier provided in the first aspect is used; the method comprises the following steps:
step 10, according to the preset depth, the preset thickness and the preset length of the barrier, carrying out sectional manufacturing along the preset extending direction of the barrier;
wherein the manufacturing of the single-segment barrier segment comprises in particular:
step 201, the walking base moves from a start point of the single-segment barrier section to an end point of the single-segment barrier section along a preset extending direction of the barrier; in the moving process, the gel material and the in-situ soil are mixed by the stirring assembly to form a first-stage barrier section;
step 202, starting a vibration driving assembly to enable the stirring assembly to vibrate axially along the stirring assembly relative to the vibration type traction arm; the walking type base moves from the end point of the single-section barrier section to the start point of the single-section barrier section along the preset extending direction of the barrier; in the moving process, the stirring assembly stirs air with the first-stage barrier section to form a second-stage barrier section;
Step 203, the walking base moves from the start point of the single-segment barrier section to the end point of the single-segment barrier section along the preset extending direction of the barrier; in the moving process, the stirring assembly stirs the second-stage barrier section to form a third-stage barrier section; the fabrication of the single-segment barrier segment is completed.
As a further improvement of the embodiment of the present invention, in the step 202 and the step 203, the vibration frequency of the stirring assembly is set according to the in-situ geological condition of the location of the single-stage barrier section; in step 202, the moving speed of the traveling base is set according to the in-situ geological condition of the location of the single-stage barrier section.
As a further improvement of the embodiment of the present invention, setting the vibration frequency of the stirring assembly according to the in-situ geological condition of the position where the single-section barrier section is located specifically includes:
Step 211, detecting and obtaining the foundation bearing capacity of the starting point and the end point of the single-section barrier section; obtaining the top surface depth and the bottom surface depth of each soil layer of the starting point according to the foundation bearing capacity of the starting point; obtaining the top surface depth and the bottom surface depth of each soil layer of the terminal according to the foundation bearing capacity of the terminal; taking the preset depth of the barrier as the bottom depth of a soil layer where the bottom ends of the barrier barriers at the starting point and the finishing point are positioned;
Step 212, obtaining the thickness of each soil layer of the starting point according to the top surface depth and the bottom surface depth of each soil layer of the starting point; obtaining the thickness of each soil layer of the terminal according to the top surface depth and the bottom surface depth of each soil layer of the terminal; according to the thickness of each soil layer of the starting point and the thickness of each soil layer of the end point, obtaining the average thickness of each soil layer between the starting point and the end point;
Step 213, obtaining the center line depth of each soil layer of the starting point according to the top surface depth and the bottom surface depth of each soil layer of the starting point; obtaining the center line depth of each soil layer of the terminal according to the top surface depth and the bottom surface depth of each soil layer of the terminal; obtaining the average foundation bearing capacity of each soil layer between the starting point and the end point according to the foundation bearing capacity of the center line depth of each soil layer of the starting point and the center line depth of each soil layer of the end point;
Step 214, calculating the vibration frequency of the stirring assembly when the single-stage barrier is manufactured by using formula (1):
(1)
In the formula,Representing the vibration frequency of the stirring assembly in Hz when the i-th barrier segment is manufactured; the average thickness of the 1 st soil layer between the starting point and the end point of the i-th barrier section is expressed in m; the average foundation bearing capacity of the 1 st soil layer between the starting point and the end point of the i-th barrier section is expressed in MPa; The average thickness of the 2 nd soil layer between the starting point and the end point of the i-th barrier section is expressed in m; The average foundation bearing capacity of the 2 nd soil layer between the starting point and the end point of the i-th barrier section is expressed in MPa; The average thickness of the nth soil layer between the starting point and the end point of the ith barrier section is expressed in m; the average foundation bearing capacity of an nth soil layer between a starting point and an end point of an ith barrier section is expressed in MPa; representing a predetermined depth of the barrier; representing a first preset coefficient, wherein the unit is Hz; Representing a second preset coefficient, wherein the unit is Hz-MPa-1; Represents the total number of barrier segments and n represents the total number of soil layers.
As a further improvement of the embodiment of the present invention, the moving speed of the walking base is calculated according to the in-situ geological condition of the position of the barrier by using the formula (2):
(2)
In the formula,Representing the speed of movement of the walking base in step 202 in m/min when the i-th barrier segment is manufactured; representing a third preset coefficient, wherein the unit is m/min; The fourth preset coefficient is expressed in m.min-1·MPa-1.
As a further improvement of the embodiments of the present invention,The range of the value of (2) is 30-60,The range of the value of (2) is 8-12,The range of the value of (2) is 1.8-2.2,The value range of (2) is 0.08-0.12.
As a further improvement of the embodiment of the present invention, in the step 201, the moving speed of the walking base is 1.0m/min; in the step 203, the moving speed of the walking base is 2.0m/min.
Compared with the prior art, the technical scheme of the invention has the following beneficial effects:
(1) According to the device for manufacturing the barrier in the polluted site, the stirring assembly is connected with the vibration type traction arm through the vibration driving assembly, and the mixing efficiency of the cementing material and the in-situ soil is improved through vibration of the stirring assembly during mixing, so that the homogeneity of the barrier is improved, the effect of blocking pollutants is effectively improved, the mixing time is shortened, and the manufacturing efficiency is improved. The device construction area is little, does not need on-the-spot installation, and the construction can begin to arrive at the scene, can effectively improve manufacturing efficiency, and applicable in the restricted place of operation area. In addition, the vibration type traction arm is connected with the walking type base through the rotation driving assembly, and the stirring assembly can be fixed in the horizontal direction along with the vibration type traction arm in a non-working state and move along with the walking type base without disassembling the stirring assembly, so that the device has good transition efficiency.
(2) The invention provides a fine manufacturing method of a barrier in a polluted site, which is used for manufacturing the barrier in a segmented manner; when the single-section barrier section is manufactured, the walking type base moves from the starting point of the single-section barrier section to the end point of the single-section barrier section, and the gel material and the in-situ soil are mixed by the stirring component to form a first-stage barrier section; then starting the vibration driving assembly to enable the stirring assembly to vibrate along the axial direction of the stirring assembly; the walking type base moves from the end point of the single-section barrier section to the starting point of the single-section barrier section, and the stirring component stirs air with the first-stage barrier section to form a second-stage barrier section; finally, the walking type base moves from the starting point of the single-section barrier section to the end point of the single-section barrier section, and the stirring assembly stirs the second-stage barrier section to form a third-stage barrier section; thereby completing the manufacture of the single segment barrier segment. According to the invention, through mixing in three stages, the gel material and the in-situ soil are mixed in an intensified manner, and bubbles in the gel material and the in-situ soil are removed. In the first stage, the gel material is mixed with the in-situ soil to realize the mixing of the gel material with sand, silt and clay in the in-situ soil. Because the spatial distribution of the components is larger, the components can be primarily mixed without starting a vibration mode of the stirring assembly, and the cementing material, the sand, the silt and the clay are uniformly distributed in the whole depth range of the barrier. Because the stratum distribution is not completely broken at the initial stage of mixing, if air is injected in the process, disturbance and pollution migration of underground water in a permeable layer can be caused, so that the pollution migration risk of a site is increased, and air is not introduced at the first stage. In the second stage, the cementing material, the sand, the silt and the clay are initially mixed, the permeable layer is disappeared, and the barrier has a certain barrier capability, so that the fluidity of the barrier material can be increased by introducing air, the mixing efficiency is improved, and the process can not cause the large-scale migration of polluted groundwater. In addition, in this stage, the sand particles are already dispersed in fine-grained cohesive soil (silt and clay) and colloid (cementing material), so that conventional mixing is difficult to further disperse, and after the stirring assembly starts the vibration mode, the colloid generated by the cementing material and the aggregate formed by the colloid and the fine particles are gradually converted into suspension under the vibration cutting action, so that the fluidity of the suspension is increased. In this stage, by injecting air and turning on the vibration mode of the stirring assembly, sufficient stirring of the barrier and sufficient utilization of energy can be achieved. The third stage mainly realizes that bubbles in the barrier are expelled under the more uniform mixing condition. Since injected air will exist in the barrier to form voids and holes, thereby creating a dominant channel for contaminant migration, the air bubbles therein need to be dislodged. The vibration mode is performed under the vibration mode, and the barrier material can be prevented from being converted into the network colloid from the suspension, so that the difficulty in expelling bubbles is reduced.
(3) According to the method for finely manufacturing the barrier in the polluted site, the vibration frequency of the stirring assembly during construction of the barrier sections is determined according to the foundation bearing capacity of the soil layer of the site where each barrier section is located and the preset depth of the barrier. Barrier crossing formations often involves a strongly permeable layer (sand, silt) and requires embedding the barrier substrate into a weakly permeable layer (clay) and thus often complicates the sealing of soil particles within the barrier construction. Since the stirring assembly operates in a vibratory mode, a significant energy input (about 3-5 times that of the non-vibratory mode) is required, and thus a balance between the homogeneous mixing of the barrier material and the energy consumption is sought. According to the geological conditions, the thickness of each stratum is quantitatively calculated to refine the vibration frequency of the stirring cutter, so that the homogeneous mixing of the barrier materials is realized, and the construction energy consumption is reduced.
Detailed Description
The following describes the technical scheme of the invention in detail.
The embodiment of the invention provides a pollution site barrier manufacturing device, which is shown in fig. 1 and 2, and comprises a walking base 1, a vibrating traction arm 2 and a stirring assembly 3, wherein the vibrating traction arm 2 is connected with the walking base 1 through a rotation driving assembly, and the stirring assembly 3 is connected with the vibrating traction arm 2 through the vibration driving assembly. The rotation driving component is used for driving the vibration type traction arm 2 to drive the stirring component 3 to rotate relative to the walking base 1. The vibration driving component is used for driving the stirring component 3 to vibrate along the axial direction of the stirring component 3 relative to the vibration type traction arm 2. The positioning and signal interactors 4 are mounted on the walking base 1. The contaminated site barrier manufacturing apparatus of this embodiment further comprises a first discharge pipe 501 and a second discharge pipe 502, both the first discharge pipe 501 and the second discharge pipe 502 being fixed to the stirring assembly 3. The first discharge pipe 501 is used for conveying gel materials, and the second discharge pipe 502 is used for conveying air.
In the above embodiment, the walking base 1 is provided with a walking mechanism, and can walk on the ground. The manufacturing apparatus is moved to a designated position by the traveling mechanism according to the barrier position. The walking type base 1 occupies a small area. Before walking, the rotation driving component drives the vibration type traction arm 2 to drive the stirring component 3 to rotate, so that the stirring component 3 is in a horizontal state, and the walking type base 1 normally walks. When the walking base 1 stops walking and a barrier is built in the stratum soil, the rotation driving assembly drives the vibration type traction arm 2 to drive the stirring assembly 3 to rotate, so that the stirring assembly 3 is in a vertical state, and the bottom of the stirring assembly 3 is positioned in the stratum soil.
The gel material is conveyed into the stirred soil through the first discharging pipe, and the air is conveyed into the stirred soil through the second discharging pipe, so that the manufacturing of the barrier is realized.
As a preferred example, as shown in fig. 2, the stirring assembly 3 includes a stirring arm 301 and a stirring cutter 302, the stirring arm 301 is mounted on the vibration-type traction arm 2 by a vibration-driving assembly, and the stirring cutter 302 is mounted on the stirring arm 301. The stirring cutter comprises a power wheel 3021, a guide wheel 3022, a bracket 3023, a chain 3024, stirring blades 30241 and a stirring driver. The bracket 3023 is fixedly connected to the stirring arm 301. The power wheel 3021 and the guide wheel 3022 are respectively installed at two ends of the bracket 3023, and the chain 3024 is sleeved on the power wheel 3021 and the guide wheel 3022. The stirring driver is connected to the power wheel 3021, and drives the power wheel 3021 to rotate. A plurality of stirring blades 30241 are mounted on the chain 3024 at intervals along the chain 3024 for one revolution.
In operation, the stirring driving member is turned on, and the stirring driving member drives the power wheel 3021 to rotate, so as to drive the chain 3024 and the guide wheel 3022 to rotate. In this way, the stirring blade 30241 fixedly attached to the chain 3024 also rotates. Through the effect between stirring vane 30241 and the soil, realize stirring purpose. During operation of the stirring blades 30241, a slurry vortex of stable shape is formed around the chain 3024, promoting uniform mixing of the cementitious material with the in-situ soil.
Preferably, the rotation driving assembly comprises a rotation driving piece and a traction shaft 101, the vibration type traction arm 2 is connected with the walking base 1 through the traction shaft 101, and the traction shaft 101 is horizontally arranged. The rotary drive is mounted on the oscillating traction arm 2 or the walking base 1 and is connected to the traction shaft 101. In operation, the rotary drive drives the oscillating traction arm 2 in rotation about the traction axis 101.
Preferably, the vibration driving assembly comprises two motors 201 and two power shafts 202 which rotate reversely, the two motors 201 are arranged on the vibration type traction arm 2, one ends of the two power shafts 202 are respectively connected with the two motors 201, and the other ends of the two power shafts are connected with two oval limiting holes formed in the stirring arm 301 of the stirring assembly 3. The vibration type traction arm 2 is provided with a limiting guide rail 203 which is axially arranged along the bracket, and the stirring arm 301 is in sliding connection with the limiting guide rail 203 through a roller. The two motors 201 rotating in opposite directions respectively drive the two power shafts to move along the elliptical limiting holes, so that the stirring assembly axially reciprocates along the bracket to form vibration.
The embodiment of the invention also provides a method for finely manufacturing the barrier of the polluted site, and the device for manufacturing the barrier of the polluted site provided by the embodiment is utilized. Comprising the following steps:
step 10, according to the preset depth, the preset thickness and the preset length of the barrier, the segmented manufacturing is performed along the extending direction of the barrier.
Wherein the manufacturing of the single-segment barrier segment comprises in particular:
in step 201, the walking base 1 moves from the starting point of the single-segment barrier section to the end point of the single-segment barrier section along the preset extending direction of the barrier, and in the moving process, the stirring assembly 3 stirs the gel material with the in-situ soil to form a first-stage barrier section.
Step 202, the vibration driving assembly is started, so that the stirring assembly 3 vibrates along the axial direction of the stirring assembly 3 relative to the vibration type traction arm 2. The walking type base 1 moves from the end point of the single-section barrier section to the start point of the single-section barrier section along the preset extending direction of the barrier, in the moving process, the stirring assembly 3 stirs air with the first-stage barrier section, and the uniformity of the cementing material and in-situ soil is increased through the reinforced disturbance and vibration of the air, so that the second-stage barrier section is formed.
In step 203, the walking base 1 moves from the starting point of the single-stage barrier section to the end point of the single-stage barrier section along the preset extending direction of the barrier, and in the moving process, the stirring assembly 3 stirs the second-stage barrier section to expel the gas in the barrier to form the third-stage barrier section. Thereby completing the manufacture of the single segment barrier segment.
Preferably, in step 202 and step 203, the vibration frequency of the stirring assembly 3 is set according to the in-situ geological conditions where the single-stage barrier section is located. In step 202, the moving speed of the traveling base 1 is set according to the in-situ geological condition of the location where the single-stage barrier section is located.
Due to the colloid characteristic of the cementing material in the barrier, the cementing material is gradually converted into suspension from the network colloid under the vibration condition, and the suspension is converted into the network colloid after vibration is stopped. In order to realize that the gel material and bubbles in the in-situ soil can be effectively expelled in the third stage, the invention optimizes the moving speed of the walking base in the second stage, and the time between the end point of the single-stage barrier section and the mixing of the single-stage barrier section in the second stage, namely the total time from the end point to the starting point of the walking base in the second stage and from the starting point to the end point in the third stage, is longer than the time for converting the colloidal material in the barrier of the end point from suspension into network colloid. According to the invention, the energy consumption in the construction process can be reduced and the mixing uniformity of the barrier material can be improved by optimizing the moving speed of the walking type base.
Preferably, the vibration frequency of the stirring assembly 3 is set according to the in-situ geological condition of the position of the single-section barrier section, and specifically comprises:
Step 211, detecting and obtaining the foundation bearing capacity of the starting point and the end point of the single-section barrier section. The formation loading force is cone tip resistance, sidewall resistance or total penetration resistance. And dividing the stratum according to the foundation bearing capacity of the starting point and the finishing point, wherein the total number of the stratum is n. And obtaining the top surface depth and the bottom surface depth of each soil layer of the starting point according to the foundation bearing capacity of the starting point. And obtaining the top surface depth and the bottom surface depth of each soil layer of the terminal according to the foundation bearing capacity of the terminal. And taking the preset depth of the barrier as the bottom depth of the soil layer where the bottom ends of the barrier barriers are positioned at the starting point and the ending point. For example, the preset depth of the barrier is 7m, the bottom depth of the 2 nd soil layer from top to bottom (i.e. the top depth of the 3 rd soil layer) at the starting point is 6.05m, the bottom depth of the 3 rd soil layer is greater than 7m, i.e. the bottom end of the barrier is located at the 3 rd soil layer, and the bottom depth of the 3 rd soil layer taking 7m as the starting point.
And step 212, subtracting the top surface depth from the bottom surface depth according to the top surface depth and the bottom surface depth of each soil layer of the starting point to obtain the thickness of each soil layer of the starting point. And subtracting the top surface depth from the bottom surface depth according to the top surface depth and the bottom surface depth of each soil layer at the end point to obtain the thickness of each soil layer at the end point. Based on the thickness of each soil layer at the starting point and the thickness of each soil layer at the end point, usingAnd calculating to obtain the average thickness of each soil layer between the starting point and the end point. In the formula,Represents the average thickness of the jth soil layer between the start point and the end point of the ith barrier section,The thickness of the jth soil layer representing the start of the ith barrier section,The thickness of the jth soil layer representing the end point of the ith barrier segment.
And step 213, obtaining the midline depth of each soil layer of the starting point according to the top surface depth and the bottom surface depth of each soil layer of the starting point. And obtaining the center line depth of each soil layer of the terminal according to the top surface depth and the bottom surface depth of each soil layer of the terminal. Based on the foundation bearing capacity of the central line depth of each soil layer of the starting point and the central line depth of each soil layer of the end point, the method utilizesAnd calculating to obtain the average foundation bearing capacity of each soil layer between the starting point and the end point. In the formula,Represents the average foundation load capacity of the jth soil layer between the starting point and the end point of the ith barrier section,The foundation bearing capacity of the center line depth of the j-th soil layer representing the starting point of the i-th barrier segment,Foundation load capacity of the center line depth of the j-th soil layer representing the end point of the i-th barrier segment.
Step 214, calculating the vibration frequency of the stirring assembly when manufacturing the single-stage barrier segment by using formula (1):
(1)
In the formula,Representing the vibration frequency of the stirring assembly in Hz when the i-th barrier segment is manufactured; the average thickness of the 1 st soil layer between the starting point and the end point of the i-th barrier section is expressed in m; the average foundation bearing capacity of the 1 st soil layer between the starting point and the end point of the i-th barrier section is expressed in MPa; The average thickness of the 2 nd soil layer between the starting point and the end point of the i-th barrier section is expressed in m; The average foundation bearing capacity of the 2 nd soil layer between the starting point and the end point of the i-th barrier section is expressed in MPa; The average thickness of the nth soil layer between the starting point and the end point of the ith barrier section is expressed in m; the average foundation bearing capacity of an nth soil layer between a starting point and an end point of an ith barrier section is expressed in MPa; representing a predetermined depth of the barrier; representing a first preset coefficient, wherein the unit is Hz; Representing a second preset coefficient, wherein the unit is Hz-MPa-1; Represents the total number of barrier segments and n represents the total number of soil layers. Preferably, the method comprises the steps of,The range of the value of (2) is 30-60,The range of the value of (2) is 8-12.
Because the barrier is a linear structure that spans a long distance, formations along the line may change, particularly for complex formations formed by impacts along rivers, and the like. The number of soil layers traversed within a predetermined depth of the barrier, the thickness of each layer, the nature of the soil, etc. can have an impact on the homogeneity and service performance of the barrier. For example, if only sand is penetrated through the stratum, after the cementing material and the sand are mixed, the agglomeration of the cementing material and the sand is weaker, so that the difficulty of uniform mixing is smaller, and the stirring can be completed under the condition of low-frequency vibration of the stirring assembly; however, when a large amount of fine-grained clay (silt and clay) is penetrated through the stratum, the cementing material and the clay particles are cemented to form an aggregate, and at this time, effective mixing of sand and the aggregate is difficult to achieve, so that more kinetic energy is required to be provided for sand grains under the condition of high-frequency vibration, so that the sand grains can enter the aggregate to form a stable network colloid-sand core structure. According to the embodiment of the invention, according to geological conditions, the thickness of each stratum is quantitatively calculated to carry out fine design on the vibration frequency of the stirring assembly, so that the homogeneous mixing of the barrier materials is realized, and the construction energy consumption is reduced.
Preferably, the moving speed of the walking base is calculated by using the formula (2) according to the in-situ geological condition of the position of the blocking barrier:
(2)
In the formula,Representing the speed of movement of the walking base in step 202 in m/min when the i-th barrier segment is manufactured; representing a third preset coefficient, wherein the unit is m/min; the fourth preset coefficient is expressed in m.min-1·MPa-1. Preferably, the method comprises the steps of,The range of the value of (2) is 1.8-2.2,The value range of (2) is 0.08-0.12.
Preferably, in step 201, the moving speed of the walking base is 1.0m/min. In step 203, the moving speed of the walking base is 2.0m/min.
A specific example is provided below.
The soil of a certain polluted site is polluted with groundwater, and a barrier is constructed at the boundary of the site in order to control the downstream migration of the pollutants in the soil of the site and the groundwater in the direction of groundwater flow. By earlier design, the barrier was 7.0 m a deep, 0.8 a m a thick and 60m long. The barrier length was designed and built with 30m as one segment, and two segments of barrier were built up in total.
Geological survey is first conducted before the approach to the manufacturing of the barrier. And detecting stratum bearing capacity parameters within preset depths of the starting point and the end point of each barrier segment. 3 in-situ test points are distributed along the extending direction of the barrier, as shown in fig. 3, and are a first test point 801, a second test point 802 and a third test point 803 respectively. The first test point is the start point of the first segment of the barrier, the second test point 802 is the end point of the first segment of the barrier, and also the start point of the second segment of the barrier, and the third test point 803 is the end point of the second segment of the barrier. The cone tip resistance obtained by in-situ double-bridge probe test in this example is used as the bearing capacity of the foundation. According to the detected bearing capacity of the foundation, three geological layers, namely a first soil layer 601, a second soil layer 602 and a third soil layer 603, which are respectively spanned from top to bottom within the depth range of 7.0m are obtained, as shown in fig. 4.
Manufacturing parameter design of the first segment of barrier:
The thickness of the three soil layers at the start of the first barrier segment is obtained as shown in table 1.
Table 1 soil layer parameters of the start of the first Barrier section
The thicknesses of the three soil layers at the end of the first barrier segment are shown in table 2.
Table 2 soil layer parameters at the end of the first barrier section
And calculating to obtain the average thickness of the first section of the blocking barrier section from top to bottom to be 1.81m, 3.87m and 1.33m.
And detecting to obtain cone tip resistance of the central line depth of the three soil layers between the starting point and the end point of the first barrier section, and calculating to obtain average cone tip resistance of each soil layer between the starting point and the end point of the first barrier section, wherein the average cone tip resistance is shown in Table 3. Since the preset depth of the barrier in this embodiment is 7m, only a part of the barrier within the depth range (the minimum submerging depth is 0.95m, and the maximum submerging depth is 1.70 m) submerges into the third soil layer, so that the cone tip resistance of the barrier embedded at the depth of 1/2 of the depth of the third soil layer (i.e. the position 0.48m below the top surface of the third soil layer at the starting point and the position 0.85m below the top surface of the third soil layer at the end point) is used as the cone tip resistance of the midline depth of the layer.
TABLE 3 cone tip resistance of first segment Barrier segment
And (3) calculating the vibration frequency of the stirring assembly when the first barrier section is manufactured by using the formula (1), wherein in the formula (1), a=50 Hz and b= Hz.MPa-1, the vibration frequency of the stirring assembly in the second stage and the third stage when the first barrier section is manufactured is 110.4Hz, the vibration frequency is downwards an integer multiple of 5, and the vibration frequency is 110Hz.
The moving speed of the traveling base at the second stage when the first barrier segment was manufactured was calculated by using the formula (2), wherein in the formula (2), c=2.00 m/min and d=0.10 Hz ·mpa-1, and the moving speed of the traveling base at the time of manufacturing the first barrier segment was 1.40 m/min.
In order to compare the vibration of the stirring assembly and the influence of compressed air in the stirring process on the dirt intercepting effect of the constructed barrier, the first barrier section is constructed by dividing the first barrier section into 5 subsections, and the length of each subsection is 6m. Wherein, the construction parameters of 5 subsections are shown in Table 4. In Table 4, vibration indicates the stirring assembly on vibration mode with a vibration frequency of 110Hz. Other construction parameters of the 5 subsections are the same.
Construction process of table 45 sub-section
The steps for manufacturing the 1 st subsection of the first segment barrier segment are as follows:
Step (1) the walking base 1 is moved to the start of the 1 st sub-section and keeps the axis of the manufacturing apparatus consistent with the barrier extension direction.
And (2) starting a stirring driving piece of the stirring assembly 3 to enable the chain 3024 to drive the stirring blade 30241 to rotate, wherein the rotation speed is controlled to be 2.5rad/min.
Step (3) the walking base 1 is kept still, the rotation driving assembly is started, the vibration type traction arm 2 and the stirring assembly 3 are driven to rotate around the traction shaft 101, and the rotation speed is properly adjusted according to the soil quality of the stratum soil until the stirring cutter 302 is in a vertical state.
Step (4) spraying the cement-based cementing material through a first discharge pipe 501 and contacting with in-situ soil. The cementing material and the in-situ soil are mixed under the action of the stirring assembly 3. At this time, the stirring assembly 3 is in a static operation state (non-vibration operation state). The walking base 1 runs along the extending direction of the barrier, the running speed is 1.0m/min, and after the running reaches the end point of the 1 st subsection, the spraying of the cementing material is stopped. To this end, the first stage barrier segment of the 1 st subsection is completed.
Step (5) the walking base 1 is kept still, the rotation driving assembly is started, the vibration type traction arm 2 and the stirring assembly 3 are driven to rotate around the traction shaft 101, and the stirring cutter 302 is in an inclined state, and the included angle between the stirring cutter and the vertical surface is 15 degrees.
And (6) starting a vibration driving assembly, wherein the vibration frequency is 110Hz, and driving the stirring assembly to vibrate along the axial direction of the stirring assembly relative to the vibration type traction arm. Compressed air is ejected through the second discharge pipe 502 and contacts the first stage barrier segment. The traveling base 1 travels along the barrier extension direction at a travel speed of 1.40m/min, returning from the end point of the 1 st subsection to the start point of the 1 st subsection. After traveling to the start point of the 1 st subsection, the compressed air is stopped from being ejected. To this end, the second stage barrier segment of the 1 st subsection is completed.
Step (7) the walking base 1 is kept still, the rotation driving assembly is started, the vibration type traction arm 2 and the stirring assembly 3 are driven to rotate around the axis of the traction shaft 101, and the stirring cutter 302 is in an inclined state, and the included angle between the stirring cutter and the vertical surface is 30 degrees.
And (8) running the walking base 1 along the extending direction of the barrier, wherein the running speed is 2.0m/min, and the stirring driving piece of the stirring assembly 3 is closed from the starting point of the 1 st subsection to the end point of the 1 st subsection. Thus, the 1 st subsection is completed.
And (3) repeating the steps (1) to (8) to build the rest fields according to the construction process of the table 4, thereby completing the construction of the first barrier section.
After 28 days of curing, samples at depths of 1.0m, 3.0m and 6.0m were collected at the middle position of each sub-section, and the permeability coefficient of the samples was tested with reference to the geotechnical test method Standard (GB/T50123-2019). Obtaining three test values of samples at different depth positions, and taking the average value of the test values, wherein the average value of the permeability coefficients of the five subsections is respectively 2.15×10-7cm/s、6.50×10-6cm/s、7.03×10-7cm/s、2.37×10-7cm/s、2.91×10-7cm/s.
Comparing the 1 st subsection, the 2 nd subsection and the 3 rd subsection, the vibration process of the second stage and the third stage can be found, so that the stirring efficiency can be obviously increased, and the permeability coefficient of the barrier can be reduced. Comparing the 1 st subsection, the 4 th subsection and the 5th subsection, the vibration and gas injection process in the first stage can be found that the permeability coefficient of the barrier is not reduced, and the permeability coefficient of the barrier is slightly increased after vibration and gas injection in the first stage, so that the first stage is not suitable for starting vibration and gas injection. The first stage causes migration of a pollution area through vibration and gas injection, so that the underground water pollution concentration of the barrier construction position is increased, the hydration process of the cementing material is inhibited, and the permeability coefficient is increased.
Manufacturing parameter design of the second section barrier section:
the thickness of the three soil layers at the start of the second barrier segment is obtained as shown in table 5.
Table 5 soil layer parameters of the start of the second Barrier section
The thicknesses of the three soil layers at the end of the second barrier segment are shown in table 6.
Table 6 soil layer parameters at the end of the second Barrier section
And calculating to obtain the average thickness of the second section of the blocking barrier section from top to bottom of the three soil layers to be 2.59m, 1.99m and 2.43m.
And detecting to obtain cone tip resistance of the central line depth of the three soil layers between the starting point and the end point of the second barrier section, and calculating to obtain average cone tip resistance of each soil layer between the starting point and the end point of the second barrier section, wherein the average cone tip resistance is shown in Table 7. Since the preset depth of the barrier in this embodiment is 7m, only a part of the barrier within the depth range (the minimum penetration depth is 1.70m, the maximum penetration depth is 3.15 m) is penetrated into the third soil layer, so that the cone tip resistance of the barrier at the depth of 1/2 of the depth of the third soil layer (i.e. at the position 0.85m below the top surface of the third soil layer at the starting point and at the position 1.58m below the top surface of the third soil layer at the end point) is adopted as the cone tip resistance of the midline depth of the layer.
TABLE 7 Cone tip resistance of the second Barrier segment
And (3) calculating the vibration frequency of the stirring assembly when the second barrier section is manufactured by using the formula (1), wherein in the formula (1), a=50 Hz and b=10 Hz-MPa-1, so that the vibration frequency of the stirring assembly in the second stage and the third stage when the second barrier section is manufactured is 99Hz, the vibration frequency is downwards an integer multiple of 5, and the vibration frequency is 95Hz.
Calculating the moving speed of the walking base when the second barrier section is manufactured by using the formula (2), wherein in the formula (2), c=2.00 m/min and d=0.10 Hz-MPa-1, and the moving speed of the walking base in the second stage when the second barrier section is manufactured is 1.51 m/min.
In order to compare the influence of the vibration frequency of the stirring assembly and the moving speed of the walking base on the dirt intercepting effect of the constructed barrier, the second barrier section is constructed by dividing the second barrier section into 5 subsections, and the length of each subsection is 6m. Wherein, the construction parameters of 5 subsections are shown in Table 8. Other construction parameters of the 5 subsections are the same.
Construction process of table 85 sub-section
And (3) repeating the steps (1) to (8) for constructing 5 sub-sections according to the construction process shown in table 8, thereby completing the construction of the second barrier section.
After 28 days of curing, samples were collected at the intermediate positions of each sub-section at depths of 1.0m, 3.0m and 6.0m, and the permeability coefficients of the samples were tested. Obtaining three test values of samples at different depth positions, taking the average value of the test values, wherein the average value of permeability coefficients of 5 sub-segment barrier barriers is respectively 2.32×10-7cm/s、1.53×10-6cm/s、2.35×10-7cm/s、2.27×10-7cm/s、8.11×10-7cm/s.
Comparing the 1 st, 2 nd and 3 rd sub-sections, it can be seen that the permeability coefficient of the barrier increases (2 nd sub-section) at vibration frequencies below 95Hz, whereas the permeability coefficient of the barrier is substantially unchanged (3 rd sub-section) at vibration frequencies above 95 Hz. Comparing the 1 st subsection, the 4 th subsection and the 5 th subsection, it can be found that the permeability coefficient of the barrier is basically unchanged (the 4 th subsection) when the moving speed of the walking type base is lower than 1.51 m/min, and the permeability coefficient of the barrier is obviously increased (the 5 th subsection) when the vibration frequency is higher than 95 Hz.
From this, it can be derived that the method of the invention uses formulas (1) and (2) to calculate the vibration frequency of the stirring assembly and the moving speed of the walking base, thus ensuring the lowest permeability coefficient of the barrier and reducing the construction energy consumption.
The foregoing has shown and described the basic principles, principal features and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the specific embodiments described above, and that the above specific embodiments and descriptions are provided for further illustration of the principles of the present invention, and that various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined in the appended claims.