Sectional type grouting and stress monitoring integrated device and method

Abstract

The invention relates to the technical field of fault fracture zone grouting, and discloses a sectional type grouting and stress monitoring integrated device which comprises an inner cylinder and a ground stress monitor. The inner cylinder comprises three grouting sections; the diameters of the three grouting sections are gradually increased from bottom to top, the joints of every two adjacent grouting sections are connected through telescopic flexible sections, and the inner side of each grouting section is provided with a grouting ring hole. According to the method, for a complex geological structure in a fault fracture zone, a loose rock stratum and a rock stratum with good stability in the fault fracture zone are regionally divided from different heights, and a plurality of grouting sections are formed. The method comprises the following steps: firstly, segmenting rock stratums in different stages, then grouting the rock stratums in different stages by adopting targeted grout, performing targeted stress detection on each grouting section so as to formulate different grouting schemes, and performing grouting work by adopting grout with different flowability and permeability, so that a better grouting reinforcement effect and grout utilization efficiency can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of fault fracture zone grouting, and in particular to a segmented grouting and stress monitoring integrated device and method. Background Art

[0002] The research on targeted grouting technology for fault fracture zones is of great significance to the implementation of actual engineering projects. Fault fracture zones are common weak zones in geological structures, characterized by rock fragmentation and highly developed fissures. However, this type of special stratum structure has extremely poor stability and low bearing capacity of surrounding rocks. It is easy to cause geological disasters such as water and mud inrush when it encounters water, posing a serious threat to the stability and safety of underground projects. Traditional grouting reinforcement methods often use a single grouting material and grouting pressure, which is difficult to adapt to the complex geological conditions of fault fracture zones, resulting in poor grouting effects and may even cause construction safety accidents.

[0003] In the existing grouting technology, sleeve valve tube grouting and grouting tube grouting technology are generally used in the grouting reinforcement plan for the fault fracture zone.

[0004] (1) The sleeve valve tube grouting process is to first drill a hole through a submerged borehole, place a stress monitoring instrument in the rock layer or borehole, and analyze the geological structure of the drilled stratum. Then inject the prepared casing material into the hole, place the sleeve valve tube in the hole, seal the upper end, and wait for the casing material to solidify to form a certain strength before grouting. During the grouting work, the sleeve valve tube grouting will be carried out in sections according to the stress changes fed back by the stress monitoring device placed during drilling, and repeated grouting will be carried out to achieve better grouting effect.

[0005] (2) Grouting pipe grouting process is relatively simple. It is to insert the corresponding grouting pipe into the borehole, place the grouting device in the grouting area, start the grouting pump, and inject the slurry into the target formation through the grouting pump to achieve the grouting reinforcement effect.

[0006] Existing sleeve valve tube grouting and grouting tube grouting schemes often use single slurry grouting, but in actual engineering, the degree of rock crack development is different for different surrounding rock conditions in the fault fracture zone, and a single grouting material cannot achieve a good grouting effect. It is necessary to use targeted grouting materials according to the regional differences in the fault fracture zone. Secondly, due to the single grouting material of the existing grouting scheme, the adjustment of grouting pressure during grouting operation is also relatively simple. It is impossible to accurately grasp the stress of the stratum in the grouting section and make timely adjustments. Under different geological structural conditions, the grouting pressure will be too high, which will further develop the rock cracks after grouting. The grouting effect cannot be reported, and it also causes a waste of grouting materials, increases construction costs and increases construction safety hazards.

[0007] Therefore, in order to achieve precise reinforcement of the fault fracture zone area, improve the grouting effect and engineering safety, the present invention provides an adjustable segmented differential grouting method for the fault fracture zone. Summary of the Invention

[0008] To solve the technical problems proposed in the background art, the present invention provides an integrated device and method for segmented grouting and stress monitoring.

[0009] The present invention is implemented by the following technical solutions: An integrated device for segmented grouting and stress monitoring includes an inner cylinder and a ground stress monitor;

[0010] The inner cylinder includes three grouting sections; from bottom to top, the diameters of the three grouting sections gradually increase, and the connection between adjacent two grouting sections is connected by a telescopic flexible section. Moreover, a grouting ring hole is provided on the inner side of each grouting section, and a plugging unit for sealing the grout is also provided on the inner side of the grouting section; a sandwich layer is provided inside the shell of the grouting section.

[0011] The stress monitor is arranged in the sandwich layer.

[0012] Specifically, each grouting section is a circular sleeve structure, the flexible section is a rubber expansion tube, and the plugging unit is a grouting plugging stopper.

[0013] Specifically, it is characterized in that sensors for monitoring the grouting pressure and grouting flow rate are also arranged in the sandwich layer.

[0014] The present invention also proposes a segmented grouting and stress monitoring method, which uses the integrated device proposed in the above scheme and includes the following steps:

[0015] Step 1: Conduct ground stress monitoring and analysis on the drilled formation, and segment the formation with different lengths, heights, and widths according to the geological characteristics, rock properties, fracture development conditions, and engineering requirements of the formation at the opening.

[0016] Step 2: According to the above analysis results, use a down-the-hole drill to carry out the opening work, and respectively excavate holes with corresponding diameters in each formation segment. The holes with different diameters correspond to different diameter grouting sections in the inner cylinder.

[0017] Step 3: Insert the inner cylinder into the hole drilled by the drill, and then put the grouting pipe into the inner cylinder, so that the slurry outlet of the grouting pipe is in the same position as the grouting ring hole reserved on the side of the grouting section. The connection between different diameter grouting sections is sealed with a grouting plugging stopper to ensure that the corresponding slurry is injected into each grouting section.

[0018] Step 4: Select different slurries for grouting according to different segments. The basis for slurry selection is as follows:

[0019] a. Before grouting, first select appropriate grouting materials according to the geological conditions and engineering requirements of the grouting section;

[0020] b. During grouting, the grouting effect can be analyzed and evaluated through the stress monitoring instrument inside the sleeve. Add appropriate inert materials according to actual needs to adjust the fluidity and setting time of the slurry, ensuring that the slurry can fully spread and fill the cracks;

[0021] Step 5. Start grouting, using a grouting device with adjustable grouting pressure;

[0022] Before grouting, a reasonable grouting pressure range should be set according to the geological conditions of the grouting section and the characteristics of the grouting materials;

[0023] During grouting, the stress change of the surrounding rock during grouting is evaluated in real time through the stress monitor placed in the circular sandwich layer of the casing. Control and adjust the grouting pressure in a timely manner according to the actual situation of the project, so as to achieve precise control of the grouting pressure in the grouting working section. This can avoid the situation that the excessive grouting pressure leads to the further development of rock cracks and secondary disasters, and the too small grouting pressure leads to the slurry unable to fully penetrate into the rock cracks.

[0024] Specifically, the grouting materials in step 4 include single-component cement slurry, cement and water glass double-component slurry, and cement quick-setting slurry; the inert materials are sand and sawdust.

[0025] Specifically, the specific operation of step 1 is as follows:

[0026] In actual engineering, the division of the grouting section can also be based on the degree of formation fragmentation and permeability, and the grouting section height can be divided by the following formula;

[0027] L = Q·t

[0028] A·n·η

[0029] In the formula, L is the grouting section height, Q is the grouting flow rate, t is the grouting time, A is the grouting area, n is the formation porosity, and η is the slurry filling coefficient (generally taken as 0.7 - 0.9). According to the divided grouting sections, drilling operations are completed on the down-the-hole drill with corresponding drill bits of diameters R1, R2, and R3 to form multiple grouting sections L1, L2, and L3.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] For the complex geological structures in the fault fracture zone, the present invention divides the loose rock strata in the fault fracture zone and the rock strata with better stability regionally from different heights to form multiple grouting sections. Then, targeted slurries are used for grouting the rock strata in different stages of each section, and targeted stress detection is carried out for each grouting section to formulate different grouting schemes. By using slurries with different fluidities and permeabilities for grouting work, better grouting reinforcement effects and slurry utilization efficiencies can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 FIG. is a schematic diagram of the sectional grouting process proposed by the present invention;

[0033] Figure 2 FIG. is a schematic cross-sectional view of the inner cylinder proposed by the present invention;

[0034] Figure 3 FIG. is a main step flow chart of a sectional grouting method proposed by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] Next, in combination with the drawings and specific embodiments, the present invention will be further described. It should be noted that, on the premise of non-conflict, any combination of the following-described embodiments or technical features can form a new embodiment.

[0036] Embodiment 1:

[0037] Referring to Figure 1 - Figure 2 , an integrated device for sectional grouting and stress monitoring proposed in this solution includes an inner cylinder and a ground stress monitor;

[0038] The inner cylinder includes three grouting sections; from bottom to top, the diameters of the three grouting sections gradually increase, the connection between adjacent two grouting sections is connected by a telescopic flexible section, and a grouting ring control is provided on the inner side of each grouting section, and a plugging unit for sealing the slurry is also provided on the inner side of the grouting section; there is a sandwich in the shell of the grouting section.

[0039] The stress monitor is arranged in the sandwich.

[0040] In this solution, a piezoelectric sensor or a piezoresistive sensor can be used for the selection of the stress monitoring sensor. Since the sensor is placed at the arc-shaped inner wall of the sleeve sandwich, the shape of the sensor should be customized according to the actual size parameters of the sleeve inner wall. The power supply wiring and data wiring of the sensor should extend through each independent sleeve sandwich until the ground and be connected to the working platform.

[0041] The grouting sections are all circular sleeve structures. The flexible section uses a rubber expansion pipe, and the plugging unit is a grouting stopper. The material of the sleeve can be selected as 316L stainless steel, and the wall thickness should be selected from 8 mm to 12 mm to cope with the formation stress changes during grouting.

[0042] Sensors for monitoring grouting pressure and grouting flow rate are also provided in the interlayer. The CJ-J6 intelligent grouting recorder can be selected, which can be used for integrated monitoring and control of grouting pressure and grouting flow rate.

[0043] Embodiment 2:

[0044] A segmented grouting and stress monitoring method proposed in this solution includes the following steps:

[0045] Step 1: When carrying out grouting work, first use a down-the-hole drill to drill holes according to the minimum diameter among the corresponding diameters of the sleeves, and conduct in-situ stress monitoring and analysis on the drilled formation. According to the geological characteristics, rock properties, fracture development conditions and engineering requirements of the drilled formation, the formation is segmented with different lengths, heights and widths.

[0046] The specific operation of Step 1 is as follows:

[0047] In engineering practice, the division of grouting sections can also be based on the formation fragmentation degree and permeability to divide the grouting section height with the following formula;

[0048] L = Q·t

[0049] A·n·η

[0050] In the formula, L is the grouting section height, Q is the grouting flow rate, t is the grouting time, A is the grouting area, n is the formation porosity, and η is the slurry filling coefficient (generally taken as 0.7 - 0.9). According to the divided grouting sections, use drill bits with corresponding diameters R1, R2, R3 on the down-the-hole drill to complete the hole-opening operation to form multiple grouting sections L1, L2, L3.

[0051] Step 2: Insert the inner cylinder into the hole drilled by the drill, then put the grouting pipe with a diameter corresponding to the inner cylinder into the inner cylinder and ensure that the slurry outlet of the grouting pipe is consistent with the position of the grouting ring hole reserved on the side of the inner cylinder. When carrying out grouting work, use a grouting stopper to plug the joints of the grouting sections with different diameters to ensure that the corresponding slurries are injected into each grouting section.

[0052] Step 3: Slurry selection for different grouting sections: First, select appropriate grouting materials according to the geological conditions and engineering requirements of the grouting section; such as single-liquid cement slurry, cement and water glass dual-liquid slurry, and cement quick-setting slurry. Then, during the grouting operation, the grouting effect can be analyzed and evaluated through the built-in stress monitoring instrument in the sleeve. According to actual needs, add an appropriate amount of inert materials (such as sand, sawdust, etc.) to adjust the fluidity and solidification time of the slurry to ensure that the slurry can fully diffuse and fill the cracks;

[0053] Step 4: Use grouting equipment with adjustable grouting pressure. Before pre-grouting, set a reasonable grouting pressure range according to the geological conditions of the grouting section and the characteristics of the grouting material; then, during the grouting operation, use the stress monitor placed in the annular interlayer of the casing to conduct real-time evaluation of the surrounding rock stress changes during the grouting process, and timely control and adjust the grouting pressure according to the actual project situation, so as to achieve precise control of the grouting pressure in the grouting section. This is to avoid the situation where excessive grouting pressure leads to further development of rock cracks and thus secondary disasters, and too low grouting pressure leads to the inability of the slurry to fully penetrate into the rock cracks.

[0054] Step 5. Since this grouting method divides the fault fracture zone into different sections and places a stress monitor in the freely adjustable casing, the purpose is to achieve a gradual reinforcement effect through refined differentiation. When performing grouting work, the slurry and grouting process should be adjusted according to the real-time data fed back by the stress monitor in the casing. The grouting process of quantitative grouting and multiple re-injections should be adopted. The re-injection time should be extended to increase the degree of slurry gelation and limit the slurry diffusion distance to obtain the most suitable grouting material and grouting pressure for the target grouting section. A combination of grouting processes such as curtain stop layer, shallow hole grouting, medium and deep hole grouting and deep hole grouting should also be adopted for actual engineering conditions to achieve better grouting effect and material utilization. The overall flow chart is as follows Figure 3 .

[0055] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A segmented grouting and stress monitoring integrated device, characterized in that: Includes inner tube and ground stress monitor; The inner tube includes three grouting sections; the diameters of the three grouting sections gradually increase from bottom to top, and the connection between two adjacent grouting sections is connected by a retractable flexible section, and a grouting ring hole is provided on the inner side of each grouting section, and a plugging unit for sealing slurry is also provided on the inner side of the grouting section; a sandwich layer is provided in the shell of the grouting section; The stress monitor is arranged in the interlayer.

2. A segmented grouting and stress monitoring integrated device as claimed in claim 1, characterized in that: The grouting sections are all circular sleeve structures, the flexible sections are rubber telescopic tubes, and the plugging units are grouting stoppers.

3. The integrated device for segmented grouting and stress monitoring according to claim 1, characterized in that: The interlayer is also provided with sensors for monitoring the grouting pressure and the grouting flow rate.

4. A segmented grouting and stress monitoring method, characterized in that: The integrated device according to any one of claims 1 to 3 comprises the following steps: Step 1: Monitor and analyze the ground stress of the drilled stratum, and divide the stratum into sections of different lengths, heights, and widths according to the geological characteristics, rock properties, fracture development, and engineering requirements of the drilled stratum; Step 2: According to the above analysis results, a down-the-hole drill is used to drill holes of corresponding diameters in each stratum, and holes of different diameters correspond to grouting sections of different diameters in the inner tube; Step 3: insert the inner tube into the borehole opened by the drilling rig, and then put the grouting pipe into the inner tube, so that the grouting outlet of the grouting pipe is consistent with the grouting ring hole reserved on the side of the grouting section, and the connection between the grouting sections of different diameters is blocked with a grouting stopper to ensure that the corresponding slurry is injected into each grouting section; Step 4: Select different slurries for grouting according to different sections. The basis for slurry selection is as follows: a. Before grouting, select appropriate grouting materials according to the geological conditions and engineering requirements of the grouting section; b. During grouting, the grouting effect can be analyzed and evaluated through the built-in stress monitoring instrument of the sleeve. According to actual needs, an appropriate amount of inert material can be added to adjust the fluidity and solidification time of the slurry to ensure that the slurry can fully diffuse and fill the cracks; Step 5, start grouting, using grouting equipment with adjustable grouting pressure; Before grouting, a reasonable grouting pressure range should be set according to the geological conditions of the grouting section and the characteristics of the grouting material; During grouting, the stress monitor placed in the annular interlayer of the casing is used to evaluate the stress changes of the surrounding rock during the grouting process in real time, and the grouting pressure is controlled and adjusted in time according to the actual situation of the project, so as to achieve precise control of the grouting pressure in the grouting section. This is to avoid the situation where excessive grouting pressure leads to further development of rock cracks and thus secondary disasters, and too low grouting pressure leads to the inability of the slurry to fully penetrate into the rock cracks.

5. A segmented grouting and stress monitoring method as claimed in claim 4, characterized in that: The grouting material in step 4 includes single-liquid cement slurry, double-liquid slurry of cement and water glass, and cement quick-setting slurry; the inert material is sand and sawdust.

6. A segmented grouting and stress monitoring method as claimed in claim 4, characterized in that: The specific operations of step 1 are as follows: In engineering practice, the division of grouting sections can also be based on the degree of stratum fragmentation and permeability, and the grouting section height can be divided according to the following formula: L＝ Q·t A·n·η Where L is the grouting segment height, Q is the grouting flow rate, t is the grouting time, A is the grouting area, n is the formation porosity, and η is the slurry filling coefficient (generally 0.7-0.9). According to the divided grouting segments, the drilling operation is completed on the down-the-hole drilling rig with drill bits of corresponding diameters R1, R2, and R3 to form multiple grouting segments L1, L2, and L3.

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