CN-121977932-A - Small fault-surrounding rock damage test method

CN121977932ACN 121977932 ACN121977932 ACN 121977932ACN-121977932-A

Abstract

The application provides a small fault-surrounding rock damage test method which comprises the following steps of S1, prefabricating a triaxial loading damage seepage sealing cabin body, S2, preparing samples, S3, performing tests, namely performing small fault-containing rock sample damage tests at room temperature, dividing the tests into 3 groups, wherein each group comprises 5 samples, each group of samples is subjected to 3 loading stages, and analyzing damage characteristics of the small fault samples under different conditions and damage seepage rules of the small fault samples under different conditions in a stress state of original rock, and S4. According to the application, through modifying a triaxial test system, damage seepage test researches of different samples are carried out, and the changes of sample fracture evolution, porosity and permeability characteristics caused by damage seepage of fault-containing samples under triaxial loading conditions are analyzed, so that test basis is provided for numerical simulation researches for revealing a small fault activation induced bottom plate hysteresis water bursting mechanism.

Inventors

WANG WENQIANG
LI ZHENHUA
WANG YAN
HUANG YUFENG
CHEN XU
ZHAI MINGLEI
WU QILONG
JIANG SHIJIE

Assignees

河南理工大学

Dates

Publication Date: 20260505
Application Date: 20251224

Claims (8)

1. A method of fault-surrounding rock damage failure testing, the method comprising the steps of: Step S1, prefabricating a triaxial loading damage seepage sealing cabin body, wherein the triaxial loading damage seepage sealing cabin body comprises the following components: The cylinder body comprises a cylinder body enclosing wall formed by cubes; the pressurizing cylinder body comprises a hydraulic cylinder, wherein 4 pressurizing cylinder bodies are uniformly arranged on each side surface of the cylinder body enclosing wall to form x-axis loading and corresponding y-axis loading, and 4 pressurizing cylinder bodies are also arranged at the bottom of the center of the cylinder body to form z-axis loading; The oil supply pipelines are uniformly arranged in the surrounding wall of the cylinder body and connected with the pressurizing cylinder body; the cylinder body upper pressing plate is oppositely arranged with the z-axis loading, and is provided with a water outlet; Step S2, sample preparation, comprising: S2-1, prefabricating a fault-containing rock mass, namely manufacturing cement slurry according to the proportion of sand to cement of 2:1, placing a gasket for controlling the fault angle and stainless steel sheets for simulating different faults in a mold, pouring the cement slurry into the mold, taking out the gasket after 5 hours, removing the mold after natural solidification, taking out a sample and curing; s2-2, supplementing fault fillers for the rock blocks, wherein the method comprises the steps of mixing aggregates with different particle sizes according to the thickness of a fault breaking zone, adding cement at the same time, injecting mixed liquid into the fault layer, and standing for 3 days to obtain a sample containing faults; S3, performing a test, namely performing a damage and destruction test on the rock sample containing the small fault at room temperature, wherein the test is divided into 3 groups, each group comprises 5 samples, each group of samples is subjected to 3 loading stages, and under the original rock stress state, the X-axis loading, the Y-axis loading and the Z-axis loading are preloaded to 5MPa; and S4, analyzing damage and destruction characteristics of the small fault samples under different conditions and analyzing damage and seepage rules of the small fault samples under different conditions.
2. The damage and destruction test method for the small fault-surrounding rock according to claim 1, wherein the maximum size of the triaxial loading damage seepage sealing cabin body is 290mm multiplied by 310mm, the minimum size is 270mm multiplied by 300mm, the internal cavity size of the triaxial loading damage seepage sealing cabin body is 90mm multiplied by 110mm multiplied by mm multiplied by 110mm, and the propelling compression amount of the pressurizing cylinder body is 10mm.
3. The method for damage and destruction test of small fault-surrounding rock according to claim 1, wherein the step S2-2 of supplementing the rock with fault fillers further comprises the steps of grading fault broken particles, calculating the quality of each broken stone particle grade by adopting a continuous grading formula, and the following formula is shown as follows: ; Wherein p 0 (d ≤ d i ) is the original mass ratio of small fault broken belt particles with the size smaller than d i , d i is the maximum particle size in the i group, mm, and d M is the maximum size of small fault broken belt particles, mm.
4. The method for damage and destruction test of small-fault surrounding rock according to claim 1, wherein the step S2 further comprises the steps of analyzing influences on damage and destruction seepage of small-fault by using three factors of particle grading of small-fault fracture zones, small-fault angles and small-fault fracture zone widths, wherein the particle grading of the prepared small-fault samples is 0.2, 0.3, 0.4, 0.5 and 0.6, the particle grading of the prepared small-fault samples is 2mm, 4mm, 6mm, 8mm and 10mm, and the particle grading of the prepared small-fault samples is 50 DEG, 55 DEG, 60 DEG, 65 DEG and 70 DEG.
5. The method of claim 1, wherein step S3, performing the test, comprises: S3-1, opening equipment, wherein the equipment comprises opening a pressurization cylinder body total valve; S3-2, test preloading, which comprises the steps of loading an x-axis, loading a y-axis and loading a z-axis and simultaneously providing 2.5Mpa pressure; s3-3, loading stress; and S3-4, stopping the equipment and storing test data.
6. The method of claim 5, wherein the stress loading in step S3-3 comprises: S3-3-1, performing three-axis grading loading, setting 5MPa constant pressure values to be loaded on all three axes, and finishing the loading of the stress of the original rock when X, Y, Z axes reach preset values; setting the seepage pressure to 3MPa, adjusting the preset value of the Z-axis pressure to 15MPa, adjusting the preset value of the Z-axis pressure to 0MPa after the Z-axis pressure reaches the maximum bearing value, adjusting the preset value of the Z-axis pressure to 2.5MPa after the pressure of 0MPa is continuous for 1min, and simulating the change of the stress and seepage of the bottom plate fault before and after the working face is propelled.
7. The method for fault-surrounding rock damage destruction test as claimed in claim 1, wherein the step S4 of analyzing damage destruction characteristics of the fault specimen under different conditions includes: and S4-1, analyzing damage characteristics of different crushed band particle grading samples, wherein the particle compactness of crushed band gap-filling materials is increased and the porosity is reduced along with the increase of a continuous grading coefficient n. With the increase of continuous gradation, the angle of the crack generated by the sample after the sample is loaded is gradually increased; step 4-2, analyzing damage and destruction characteristics of samples with different crushing belt widths, wherein the volume proportion of the crushed gap filler in the samples is increased along with the increase of the crushing belt widths, and the overall compressive strength is reduced; And 4-3, analyzing damage and destruction characteristics of samples with different small fault angles, wherein the angle of a fracture surface of the sample subjected to shearing damage is gradually increased along with the increase of the angle of the fracture.
8. The method for damage and destruction test of small fault-surrounding rock according to claim 1, wherein the step S4 of analyzing the damage seepage rule of the small fault sample under different conditions comprises: S4-4, analyzing the damage seepage rules of the different crushed band particle grading samples, namely analyzing the damage seepage curves of the different crushed band particle grading samples, wherein the maximum flow value is reduced along with the increase of the continuous grading coefficient; s4-5, analyzing the damage seepage rules of the particle grading samples of different crushing belts, namely analyzing the damage seepage curves of the samples under different crushing belt widths, wherein the initial seepage flow is obviously increased along with the increase of the crushing belt widths, and the flow is increased along with the increase of the strain; And S4-6, analyzing the damage seepage rules of the samples with different small fault angles, namely analyzing the damage seepage curves of the fracture samples with different angles, wherein the flow velocity shows a nonlinear increasing trend along with the increase of stress-strain.

Description

Small fault-surrounding rock damage test method Technical Field The application relates to the technical field of coal exploitation, in particular to a damage and destruction test method for small fault-surrounding rock. Background Along with the continuous increase of the exploitation depth of coal resources, the threat of high-pressure water and strong mining stress in a 'three-high one-disturbance' complex geological environment to the safe exploitation of coal seams is increasingly prominent. Engineering practice shows that even if a large number of mines strictly follow the current water control technical specifications, the mining working face hysteresis flood disaster induced by small faults still frequently occurs. The disaster-causing mechanism of the hysteresis water inrush has obvious multi-field coupling characteristics and is mainly controlled by small fault characteristics, water pressure of a bottom plate aquifer, thickness of the bottom plate aquifer and the like. The small fault damage seepage law under different mining stress paths is the basis for researching the mechanism of the base plate hysteresis water bursting induced by the small fault activation of the working face, and the small fault damage seepage instability is the root of the base plate hysteresis water bursting disaster of the coal face. The broken rock mass seepage test system related in the prior art can perform the variable mass seepage rule of the fault broken zone, but the activation of the small fault is influenced by the property of the broken zone, the stress of the upper disc and the lower disc of the small fault and the water pressure of the aquifer under the condition of mining stress. Accordingly, there is a need to provide an improved solution to the above-mentioned deficiencies of the prior art. Disclosure of Invention According to the application, a triaxial test system is changed, a cube sample penetrating through a small fault fracture zone is prefabricated, damage seepage test researches of the small fault sample under different fracture zone particle gradations, fault angles and fault fracture zone widths are carried out, the changes of sample fracture evolution, porosity and seepage characteristics caused by damage seepage of the fault-containing sample under triaxial loading conditions are analyzed, the small fault damage seepage rules under different mining stress paths are mastered, and test basis is provided for numerical simulation researches of the hysteresis water bursting mechanism of the small fault activation induced bottom plate. In order to achieve the above object, the present application provides the following technical solutions: The application provides a small fault-surrounding rock damage test method, which is improved in that the test method comprises the following steps: Step S1, prefabricating a triaxial loading damage seepage sealing cabin body, wherein the triaxial loading damage seepage sealing cabin body comprises the following components: The cylinder body comprises a cylinder body enclosing wall formed by cubes; the pressurizing cylinder body comprises a hydraulic cylinder, wherein 4 pressurizing cylinder bodies are uniformly arranged on each side surface of the cylinder body enclosing wall to form x-axis loading and corresponding y-axis loading, and 4 pressurizing cylinder bodies are also arranged at the bottom of the center of the cylinder body to form z-axis loading; The oil supply pipelines are uniformly arranged in the surrounding wall of the cylinder body and connected with the pressurizing cylinder body; the cylinder body upper pressing plate is oppositely arranged with the z-axis loading, and is provided with a water outlet; Step S2, sample preparation, comprising: S2-1, prefabricating a fault-containing rock mass, namely manufacturing cement slurry according to the proportion of sand to cement of 2:1, placing a gasket for controlling the fault angle and stainless steel sheets for simulating different faults in a mold, pouring the cement slurry into the mold, taking out the gasket after 5 hours, removing the mold after natural solidification, taking out a sample and curing; And S2-2, supplementing fault fillers for the rock blocks, wherein the method comprises the steps of mixing aggregates with different particle sizes according to the thickness of a fault breaking zone, adding cement, injecting mixed liquid into the fault layer, and standing for 3 days to obtain a sample containing faults. S3, performing a test, namely performing a damage and destruction test on the rock sample containing the small fault at room temperature, wherein the test is divided into 3 groups, each group comprises 5 samples, each group of samples is subjected to 3 loading stages, and under the original rock stress state, the X-axis loading, the Y-axis loading and the Z-axis loading are preloaded to 5MPa; and S4, analyzing damage and destruction characteristics of the small fault samples under di