TBM (Tunnel Boring Machine) behind-wall biological grouting model test device and test method
Through the TBM back-wall bio-grouting model test device and test method, the problems of uneven grouting and poor force transfer effect in the existing bean gravel backfill grouting technology are solved, and more efficient backfill layer compactness and stone body strength are achieved, reducing maintenance costs.
Patent Information
- Application Number
- CN202411904401.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-23
- Publication Date
- 2025-03-18
AI Technical Summary
The existing bean gravel backfill grouting technology has problems such as uneven grouting, destroying the integrity and strength of prefabricated pipe sheets, increasing maintenance costs, loss of grouting slurry and poor force transmission effect.
The TBM post-wall biological grouting model test device and test method are used, including visual model box, grouting system, drainage system and ultrasonic detection system. The grouting liquid composed of soy urease solution and cementitious solution is used to inject the backfill layer from bottom to top through a peristaltic pump, and the grouting is circulated until the requirements are met.
Effective simulation of the backfill layer behind the TBM wall is achieved, avoiding the hollowing and uncondensation caused by poor fluidity of cement slurry, improving the compactness of the backfill layer and the strength of the stone body, and reducing maintenance costs.
Smart Images
Figure CN119643379A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to an indoor test model for simulating biological grouting of backfill behind a TBM tunneling machine wall, and in particular to a novel simulation test platform and test method suitable for biological grouting behind a TBM wall. Background Art
[0003] During tunnel construction, due to the existence of over-excavation, there is a gap of 10~20mm between the surrounding rock and the segment lining. At present, most of the cracks are backfilled with pea gravel with a particle size of 5~10mm and then chemically grouted to form a backfill layer. The backfill layer can make the lining and the rock layer tightly combined to prevent further deformation of the surrounding rock, and correspondingly reinforce the lining and make it evenly stressed; at the same time, it blocks the gaps in the backfill layer and the cracks in the surrounding rock, which can play a good waterproof role. However, the current pea gravel backfill grouting construction technology has defects. In actual applications, the following defects are common: 1) Due to uneven grouting, the density of the backfill pea gravel is affected, which destroys the integrity and strength of the concrete on the back of the prefabricated segment; 2) The subsequent grouting work is affected by the prefabricated segment and the actual site conditions, which not only damages the prefabricated segment and reduces its strength, but also increases the maintenance cost; 3) Due to the failure to take corresponding sealing measures in time, not only the grouting slurry is lost, part of the slurry flows into the working face, affecting the on-site construction, but also it is difficult to ensure the grouting pressure, and the effect of consolidating the surrounding rock cannot be achieved, which further affects the force transmission effect of the backfill grouting layer.
[0004] In addition, the pea gravel backfill grouting process is a hidden project. After the segment ring is assembled, the pea gravel is blown in. During the blowing process, only the blowing system can be seen to send the pea gravel into the grouting hole. After the blowing is completed, the grouting is carried out. In this process, the movement and filling of the pea gravel particles in the gap between the segment and the surrounding rock, as well as the grouting quality during the grouting, cannot be known.
[0005] The backfill layer behind the TBM wall is usually constructed by blowing pea gravel into the cement slurry for reinforcement. However, due to the poor fluidity of the cement slurry and the large number of pea gravel rock powder particles, the slurry cannot fill the backfill layer. Voids are likely to appear in places where the pea gravel is not densely filled, and some pea gravel is likely to fail to solidify in densely filled places, resulting in a disconnection between the rock and the pea gravel grouting agglomerates, reducing the strength of the stone body.
[0006] my country has accumulated some experience in the application of TBM construction technology, but the research on the construction technology of pea gravel backfill grouting is not in-depth enough, and many problems have not been solved. It is necessary to combine the actual project to solve the defects of pea gravel backfill grouting and study the construction technology of pea gravel grouting backfilling. At present, in engineering applications, the mechanical properties of pea gravel backfill grouting mainly emphasize strength and anti-seepage. In addition, in engineering practice, the quality requirements of pea gravel backfill grouting layer are mostly determined by empirical methods, and there is no rigorous scientific argumentation as a basis. Therefore, whether the strength design of the backfill layer is reasonable needs to be studied. Summary of the invention
[0008] In view of the above-mentioned deficiencies in the prior art, the present invention provides a TBM back-wall bio-grouting model test device and a test method, which are helpful for simulating the actual engineering conditions of TBM back-wall backfilling.
[0009] The TBM back-wall biological grouting model test device of the present invention is characterized in that it includes a visualization model box, which is a hollow and transparent semicircular ring column structure, and the visualization model box includes a segment lining layer and a surrounding rock layer that are arranged in parallel and spaced apart in the form of semicircular arc plates, a backfill layer for injecting grouting liquid is formed between the segment lining layer and the surrounding rock layer, a sealing member is provided at the periphery of the segment lining layer and the surrounding rock layer to achieve sealing of the periphery of the backfill layer, grouting holes are arranged in an array on the segment lining layer, the grouting holes are connected to a grouting pipeline driven by a peristaltic pump, and a drainage hole for discharging waste liquid is provided at the lower edge of the visualization model box.
[0010] Preferably, the segment lining layer is formed by splicing five adjacent single rings, adjacent single rings are staggered in the circumferential direction, and each single ring is formed by splicing a number of arc-shaped segments.
[0011] Preferably, the segment lining layer and surrounding rock layer are both made of transparent acrylic panels.
[0012] Preferably, the grouting liquid is composed of a soybean urease solution and a binder liquid, which are respectively arranged in containers. There are two peristaltic pumps, and the input end of the first peristaltic pump is connected to the container of the soybean urease solution through a pipeline, and the input end of the second peristaltic pump is connected to the container of the binder liquid through a pipeline. A Y-type connector is installed on each grouting hole, and the first end of the Y-type connector is connected to the grouting hole, and the second and third ends of the Y-type connector are respectively connected to the output end pipelines of the first peristaltic pump and the second peristaltic pump.
[0013] Preferably, an ultrasonic detector is installed on the above-mentioned visualization model box, and the ultrasonic detector includes a transmitting end and a receiving end, so as to detect the binder in the backfill layer. The front and back of the visualization model box are divided into grids, and the grid nodes are ultrasonic detection points. The grid has 15 rows and 10 columns, and 15 ultrasonic detection points are correspondingly arranged on the two sides of the visualization model box.
[0014] The present invention provides a TBM back wall bio-grouting model test method, which is characterized by: (1) preparing a grouting liquid, wherein the grouting liquid is composed of a soybean urease solution and a cementing liquid, and a colorant is added to the cementing liquid to facilitate observation of the seepage path of the slurry in the pores; (2) preparing a backfill aggregate, wherein the aggregate is composed of a particle size range of 2-10 The bean gravel with a particle size range of 0.25-2 mm and the standard sand with a particle size range of 0.25-2 mm were prepared according to the mix ratio; (3) Grouting: The test adopted the single-phase grouting method, that is, soybean urease solution and cementing solution were mixed in a ratio of 1:2 and poured into the backfill layer, and the grouting holes and drainage holes were blocked to allow the reaction between the soybean urease solution and the cementing solution to be fully carried out in the model; the slurry was injected into the backfill layer from bottom to top through the grouting port by a peristaltic pump. After one cycle of reaction, the grouting was circulated until the requirements were met. The material did not solidify after grouting. The injected liquid was the cementing solution and urease solution. The urease solution would decompose the urea in the cementing solution to produce carbonate ions that combined with the calcium ions in the solution to form calcium carbonate crystals. The calcium carbonate crystals were precipitates (cementing aggregates), and the remaining liquid was waste and needed to be discharged. Since the volume injected each time was limited and the survival time of urease was limited, multiple cycles of grouting were required until the requirements were met; (4) Sample curing: After completing the set number of grouting cycles, the waste liquid was discharged and the sample was allowed to stand for curing for 7 d; (5) Ultrasonic testing: ultrasonic monitoring of the cementitious body according to the test points.
[0015] The TBM backfill model test device and test method of the present invention can well simulate the actual engineering conditions of TBM backfill. The smaller model size reduces the amount of sample tasks, and the operation difficulty and labor intensity during the test are small. The present invention has the following advantages over the traditional backfill model: 1. The TBM back-wall bio-grouting model uses a transparent acrylic plate, which can clearly observe the pea gravel backfill behind the wall, and at the same time, the penetration path in the back-wall blown fill aggregate can be observed based on the colored cementing fluid.
[0016] 2. Using EICP technology for pea gravel backfill behind the wall can avoid problems such as the inability of cement slurry to fill gaps due to poor fluidity of cement slurry, loose reinforcement of the pea gravel backfill layer, and voids.
[0017] 3. The TBM backfill bio-grouting model can well simulate the actual engineering conditions of backfill behind the wall in actual projects. Through model tests, we can study different stone-sand mix ratios, grouting times and other process parameters, so as to achieve the purpose of optimizing the grouting process. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.
[0020] Figure 1 It is a schematic diagram of the construction of the visual grouting model; Figure 2 It is a schematic diagram of the structure of the segment lining layer; Figure 3 It is a schematic diagram of the grouting process of the behind-the-wall bio-grouting model; Figure 4 It is a schematic diagram of the side view structure of the bio-grouting model behind the wall; Figure 5 It is the main view of the ultrasonic measurement points of the biological grouting model behind the wall; Figure 6 It is a side view of the ultrasonic measurement points of the bio-grouting model behind the wall; Figure 7 It is a schematic diagram of the main view of the ultrasonic test of the biological grouting model behind the wall; Figure 8 It is a schematic side view of the ultrasonic test of the behind-the-wall bio-grouting model.
[0021] The central control reset pedal and its combined connection method of the present invention are further described in detail below in conjunction with the accompanying drawings and specific implementation structures. DETAILED DESCRIPTION
[0023] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.
[0024] The TBM back wall biological grouting model test device of the present invention is divided into four parts: a visual model box, a grouting system, a drainage system and an ultrasonic detection system.
[0025] 1. Visualization Model Box Visualization model box Figure 1The figure shows a hollow semicircular cylinder, which is mainly composed of three parts: the segment lining layer 1, the surrounding rock layer 2 and the seal, each of which is made of transparent acrylic material; the inner circle of the model box is the segment lining (see Figure 2 ), with an outer diameter of 60 cm, a single ring width of 12 cm, and a total of 5 single rings with a total length of 60 cm. Adjacent single rings are spliced in a staggered manner; the whole circle of the segment lining layer adopts a six-block mode, and a grouting hole 3 with an aperture of 1.2 cm is set at the center of each segment. The model box of the present invention is a semi-structure, so each half ring is provided with 3 grouting holes; the periphery of the model box is the surrounding rock layer, with an inner diameter of 68 cm and an axial length of 60 cm. The hollow part between the segment lining layer and the surrounding rock layer is the backfill layer 4, with a size of 4 cm × 60 cm (ring width × length); in order to ensure the sealing of the model, a seal is provided at the periphery of the segment lining layer and the surrounding rock layer to achieve the closure of the periphery of the backfill layer.
[0026] 2. Grouting system The grouting system is composed of a peristaltic pump 5 with controllable flow rate. The schematic diagram of the grouting process is shown in Figure 3 As shown, the grouting liquid consists of a soybean urease solution and a cementing liquid, and the soybean urease solution and the cementing liquid are respectively arranged in a container 6. There are two peristaltic pumps, and the input end of the first peristaltic pump is connected to the container of the soybean urease solution through a pipeline, and the input end of the second peristaltic pump is connected to the container of the cementing liquid through a pipeline. A Y-type connector is installed on each grouting hole, and the first end of the Y-type connector is connected to the grouting hole 3, and the second end and the third end of the Y-type connector are respectively connected to the output end pipelines of the first peristaltic pump and the second peristaltic pump. Since the urease solution and the cementing liquid react rapidly, if they are not used in time after configuration, flocs will appear in the EICP liquid, affecting the fluidity of the slurry between aggregates. Therefore, two peristaltic pumps are used, and a Y-type connector is installed at the end of the outlet rubber tube of the peristaltic pump so that the two solutions can be mixed and poured into the visualization model box.
[0027] 3. Drainage system At the bottom of the visualization model box, five drainage ports 7 are separately set, located at the bottom of each single ring segment, so that the waste liquid can flow out of the backfill layer through the drainage ports under the action of gravity to ensure that the moisture content of aggregates in each area inside the backfill layer is close. The drainage port aperture is set to 2 cm, and the plug is removed only when the waste liquid is discharged. The drainage system is as follows: Figure 4 shown.
[0028] 4. Ultrasonic detection system An ultrasonic detector 8 is installed on the visualization model box. The ultrasonic detector uses a pile acoustic wave transmission detector produced by Sichuan Shengtuo Testing Technology Co., Ltd. The detector probe uses a pair of ultrasonic transducers with a diameter of 40 mm, which are used for transmission and reception respectively. A grid is divided on the surface of the model box, and the grid nodes are the measuring points. Figure 5is the ultrasonic measuring point arrangement diagram. The measuring points are divided into 10 columns from 1 to 10 along the axial direction, that is, 2 columns are set for each ring segment, and 15 rows are divided into a-o along the circumferential direction. There are 15 ultrasonic detection points corresponding to the two sides of the model along the axial direction, totaling 15×11=165 pairs of measuring points. The spacing between each measuring point is controlled at about 60 mm. The ultrasonic test schematic diagram is shown in Figure 6 .
[0029] The specific test process of the TBM back wall biological grouting model test device of the present invention is as follows: (1) Preparation of grouting liquid, the grouting liquid is composed of soybean urease solution and cementing liquid, and a colorant is added to the cementing liquid to facilitate the observation of the seepage path of the slurry in the pores. (2) Preparation of backfill aggregate, the aggregate is made of pea gravel with a particle size range of 2-10 mm and standard sand with a particle size range of 0.25-2 mm according to a mix ratio (which can be 1:1-1:3). In addition, in order to prevent the uneven backfilling of aggregates from affecting the study of the diffusion law of the slurry, the assembled model is placed horizontally in a radial direction before the formal grouting, and the pre-mixed aggregate is backfilled by a layered filling method, with a total filling of 60 cm, that is, the width of five rings, so as to make the aggregate filling uniform at all places in the backfill layer. (3) Grouting, the test adopts a single-phase grouting method, that is, the soybean urease solution and the cementing liquid are mixed in a ratio of 1:2 and poured into the backfill layer. The grouting holes and drainage holes are sealed to allow the reaction to fully proceed in the model. The slurry is injected into the backfill layer from bottom to top through the grouting port by a peristaltic pump. After one cycle of reaction, cyclic grouting is performed until the requirements are met. (4) Sample curing. After completing the set number of grouting cycles, the waste liquid is discharged and the sample is left to stand for curing for 7 days. (5) Ultrasonic testing. Select the "ultrasonic detection" module to monitor the ultrasonic velocity of the cementing body.
[0030] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention.
Claims
1. A TBM wall back-end bio-grouting model test device, characterized in that: The visual model box comprises a hollow and transparent semicircular cylindrical structure, the visual model box comprises a segment lining layer and a surrounding rock layer which are arranged in parallel and spaced apart in the form of semicircular plates, a backfill layer for injecting grouting liquid is formed between the segment lining layer and the surrounding rock layer, a seal is provided at the periphery of the segment lining layer and the surrounding rock layer to achieve sealing of the periphery of the backfill layer, grouting holes are arranged in an array on the segment lining layer, the grouting holes are connected to a grouting pipeline driven by a peristaltic pump, and a drainage hole for discharging waste liquid is provided at the lower edge of the visual model box.
2. The TBM back wall bio-grouting model test device according to claim 1, characterized in that: The segment lining layer is formed by splicing five adjacent single rings, adjacent single rings are staggered in the circumferential direction, and each single ring is formed by splicing a number of arc-shaped segments.
3. The TBM back wall bio-grouting model test device according to claim 2, characterized in that: The segment lining layer and the surrounding rock layer are both made of transparent acrylic plates.
4. The TBM back wall bio-grouting model test device according to claim 3, characterized in that: The grouting liquid consists of a soybean urease solution and a cementing liquid, which are respectively arranged in containers. There are two peristaltic pumps, the input end of the first peristaltic pump is connected to the container of the soybean urease solution through a pipeline, and the input end of the second peristaltic pump is connected to the container of the cementing liquid through a pipeline. A Y-type joint is installed on each grouting hole, the first end of the Y-type joint is connected to the grouting hole, and the second and third ends of the Y-type joint are respectively connected to the output end pipelines of the first peristaltic pump and the second peristaltic pump.
5. The TBM back wall bio-grouting model test device according to claim 4, characterized in that: An ultrasonic detector is installed on the visualization model box, and the ultrasonic detector includes a transmitting end and a receiving end, so as to detect the cementing body in the backfill layer. The front and back sides of the visualization model box are divided into grids, and the grid nodes are ultrasonic detection points. The grid has 15 rows and 10 columns, and 15 ultrasonic detection points are correspondingly arranged on the two sides of the visualization model box.
6. A test method for a TBM back wall bio-grouting model as claimed in any one of claims 1 to 5, characterized in that: (1) Preparation of grouting liquid. The grouting liquid consists of soybean urease solution and cementing liquid. In addition, colorant is added to the cementing liquid to facilitate the observation of the seepage path of the grouting liquid in the pores. (2) Preparation of backfill aggregate. The aggregate is made of pea gravel with a particle size range of 2-10 mm and standard sand with a particle size range of 0.25-2 mm according to the mix ratio. (3) Grouting. The test adopts the single-phase grouting method, that is, the soybean urease solution and the cementing liquid are mixed in a ratio of 1:2 and poured into the backfill layer, and the grouting holes and drainage holes are blocked to allow the reaction of the soybean urease solution and the cementing liquid to proceed fully in the model. The slurry is injected into the backfill layer from bottom to top through the grouting port through a peristaltic pump. After one cycle of reaction, the grouting is circulated until the requirements are met. (4) Sample curing. After completing the set number of grouting cycles, the waste liquid is discharged and the sample is left to cure for 7 days. (5) Ultrasonic testing. The cementing body is ultrasonically monitored according to the test points.