CN104597130A - Method for detecting and analyzing evolution process of structure of surrounding rock in area of deep tunnel of coal mine - Google Patents

Abstract

The invention discloses a method for detecting and analyzing the surrounding rock structure in the deep coal mine roadway area. The steps include: (1) arranging test boreholes in the area to be tested in the surrounding rock of the deep coal mine roadway. The depth of the area is consistent, and the digital borehole camera probe is installed and pushed in the hole in sequence to obtain the evolution law of the propagation characteristics of the sound wave in the surrounding rock between the holes; The spatial distribution of the rock volume joint number Jv; (3) Using the acoustic wave propagation of adjacent boreholes in the area as the boundary condition, the spatial distribution and evolution law of the regional surrounding rock integrity index Kv are obtained; (4) Comprehensive comparison of the surrounding rock integrity The volumetric joint number Jv of the index surrounding rock and the integrity index Kv of the regional surrounding rock can be used to obtain the evolution process of the regional surrounding rock structure. The method is easy to operate and easy to operate, and the integrity and evolution law of the surrounding rock structure before and after roadway excavation can be obtained to provide a scientific basis for the stability control and safety evaluation of the surrounding rock in deep coal mine roadways.

Description

Detection and analysis method of surrounding rock structure evolution process in deep coal mine roadway area

technical field

The invention belongs to the technical field of detection and analysis of rock mass structures, and in particular relates to a detection and analysis method suitable for the evolution process of the surrounding rock structure in the deep roadway area of coal mines.

Background technique

Affected by the geological environment and human excavation activities, there are a large number of structural planes in the surrounding rock of deep coal mine roadways. These structural planes are often the parts where the mechanical strength of the surrounding rock is relatively weak, which leads to the discontinuity, inhomogeneity and anisotropy of the mechanical properties of the surrounding rock, and their spatial distribution and combination have a great influence on the medium characteristics and mechanical properties of the surrounding rock. important influence. Therefore, it is of great significance to detect and analyze the surrounding rock structure and grasp its evolution process for the stability control and safety assessment of the surrounding rock in deep coal mine roadways.

At present, the main means of detection of surrounding rock structure is still borehole core measurement method, which is simple, convenient, intuitive and practical. However, due to the high ground stress and weak and broken characteristics of the surrounding rock in the deep coal mine, it is very difficult to collect cores, which makes it difficult to reflect the development characteristics of structural planes by drilling core measurements. The digital panoramic camera system of the borehole structural surface can obtain the image information inside the borehole through the borehole camera, and give a high-resolution 360° hole wall expansion map and three-dimensional columnar map, and then obtain the occurrence of the borehole structural surface , trace length, gap width and filler information. However, restricted by objective conditions, it is difficult for the test borehole to cover the entire area of the surrounding rock, and the information obtained through a single borehole camera can only reflect the structural characteristics of the local surrounding rock, and it is difficult to reflect the regional characteristics of the surrounding rock structure. In addition, the surrounding rock structure after the excavation of the roadway is actually changing dynamically, and it is difficult to grasp this changing process only through the borehole camera method. Therefore, there is an urgent need for a new detection and analysis method to obtain the structural evolution process of the surrounding rock in the deep coal mine roadway area, but this method has not been reported in domestic and foreign literature.

Contents of the invention

The purpose of the present invention is to provide a method for detection and analysis of the evolution process of the regional surrounding rock structure for the stability control of the surrounding rock in the deep roadway of the coal mine. In order to provide a scientific basis for the stability control and safety evaluation of surrounding rocks in deep coal mine roadways.

In order to achieve the above object, the present invention adopts the following technical measures:

A detection and analysis method applicable to the surrounding rock structure in the deep coal mine roadway area, the steps are:

(1) Arrange test boreholes (5, 9, 13, determined according to the area scope and measurement accuracy) in the area to be tested in the surrounding rock of the excavated roadway in the deep part of the coal mine, and the boreholes are respectively located at the boundary and center of the area to be tested , the boreholes are parallel to each other, and the hole depth is consistent with the area depth. For each borehole, a push digital borehole camera probe (BHCTV) is installed sequentially in the hole to collect borehole image information. Afterwards, adjacent drill holes were combined in pairs, and ultrasonic test probes (SR-RCT (B)) were installed to conduct cross-hole ultrasonic tests, and through repeated tests at different times, the propagation characteristics of sound waves in the surrounding rock between the holes were obtained over time. evolution law.

(2) According to the structural surface information of a single hole, cross-hole correlation analysis is carried out to judge the similarity of the structural surfaces of adjacent boreholes, extend or connect the structural surfaces of the boreholes, and obtain the structural surface characteristics of the surrounding rock between the holes. Furthermore, through the statistical analysis of all boreholes in the region and the surrounding rock structural plane information between the holes, the spatial distribution characteristics of the surrounding rock volume joint number Jv of the regional surrounding rock structure are obtained.

(3) Using the acoustic wave propagation characteristics of adjacent boreholes in the area as boundary conditions, invert the propagation characteristics of sound waves in the surrounding rocks of the entire area, and then analyze the integrity index of the surrounding rocks in the area to obtain the integrity index Kv of the surrounding rocks Spatial distribution characteristics and their evolution over time.

(4) Comparing the volumetric joint number Jv of the surrounding rock integrity index and the regional surrounding rock integrity index Kv comprehensively, taking the volume joint number Jv of the regional surrounding rock structure as the initial condition of the surrounding rock integrity, the regional surrounding rock integrity index The evolution law of Kv is used as the dynamic condition of the integrity of the surrounding rock to obtain the evolution process of the integrity of the regional surrounding rock structure.

Owing to having adopted above technical measure, the positive effect and the advantage of the detection and analysis method of surrounding rock structure in coal mine deep roadway area region of the present invention are:

①Based on the structural surface information of a single hole, cross-hole correlation analysis is carried out to obtain the structural surface information of the surrounding rock between holes, and then the statistical characteristics of the structural surface of the regional surrounding rock are obtained through statistical analysis, thus realizing the detection of the surrounding rock structure from the detection in the hole to the regional detected breakthroughs;

② The cross-hole ultrasonic method is used to conduct repeated tests at different times to obtain the evolution law of the integrity of the surrounding rock in the roadway area, thus realizing a breakthrough in the detection of the surrounding rock structure from static detection to dynamic detection;

③ Due to the adoption of porous layout and drilling combination scheme, the efficiency of surrounding rock structure detection and the comprehensiveness of structure surface information extraction are improved;

④Using two different testing techniques to conduct mutual verification and comparative analysis of structural surface information, which improves the accuracy and reliability of the surrounding rock structure detection results;

⑤ This method can be used not only for the structural detection of the surrounding rock of the excavated roadway, but also for the advanced detection of the surrounding rock structure of the adjacent unexcavated roadway.

⑥ This method can increase the detection range of the surrounding rock structure by more than 30 times.

Description of drawings

Figure 1 is a schematic diagram of surrounding rock selection in a roadway area.

Fig. 2 is a schematic diagram of the drilling arrangement in the surrounding rock of the roadway area.

Fig. 3 is a schematic diagram of the layout of five drilling holes in the surrounding rock of the roadway area.

Figure 4 is a schematic diagram of drilling camera.

Fig. 5 is a schematic diagram of cross-hole ultrasonic testing.

Fig. 6 is a diagram of the roadway test area and drilling layout determined in the implementation example.

Fig. 7 is the borehole image obtained in the implementation example.

Fig. 8 is the variation curve of wave velocity with hole depth obtained in the implementation example.

Fig. 9 is a spatial distribution diagram of surrounding rock structural planes analyzed and obtained in the implementation example.

Fig. 10 is the contour map of the regional surrounding rock integrity obtained from the analysis in the implementation example.

Fig. 11 is a time-dependent diagram of the regional surrounding rock integrity contour obtained from the analysis in the implementation example.

Figure 12 is a contour map of the integrity of the surrounding rock in the region before and after grouting in the implementation example.

Excavated roadway 1-1, unexcavated roadway 1-2, surrounding rock in the first area 2-1, surrounding rock in the second area 2-2, surrounding rock in the third area 2-3, first borehole 3-1 , the second borehole 3-2, the third borehole 3-3, the fourth borehole 3-4, the fifth borehole 3-5, the sixth borehole 3-6, the seventh borehole 3-7, the The eighth hole 3-8, the ninth hole 3-9, the tenth hole 3-10, the eleventh hole 3-11, the twelfth hole 3-12, the thirteenth hole 3-13, Digital borehole camera probe 4 (BHCTV), cross-hole ultrasonic test probe 5-1 (SR-RCT(B)), cross-hole ultrasonic test probe 5-2 (SR-RCT(B)).

Detailed ways

Example 1:

The present invention will be described in further detail below in conjunction with the accompanying drawings.

According to Fig. 1, Fig. 2, Fig. 3, Fig. 4, and Fig. 5, it can be known that a detection and analysis method suitable for the surrounding rock structure in the deep roadway area of coal mine, the steps are:

A. According to the project requirements, select the area to be tested around the excavated roadway 1-1. The depth of the area is 3~7 times the hole diameter. This area can be the first area surrounding rock 2-1 and the second Area surrounding rock 2-2 and the third area surrounding rock 2-3 located on the floor of the roadway. For the advanced detection of the surrounding rock structure of the adjacent unexcavated roadway, such as the unexcavated roadway 1-2, the surrounding rock 2-2 in the second area can be selected as the test area around the excavated roadway 1-1.

Test boreholes are respectively arranged at the boundary and center of the surrounding rock in the area to be tested, and the number of boreholes is at least 5, namely, the first borehole 3-1, the second borehole 3-2, the third borehole 3-3, and the third borehole. The fourth borehole 3-4, the fifth borehole 3-5, if the area to be tested is large, the sixth borehole 3-6, the seventh borehole 3-7, the eighth borehole 3-8, The ninth borehole 3-9, if the area to be measured is large and requires high measurement accuracy, the tenth borehole 3-10, the eleventh borehole 3-11, and the twelfth borehole 3-10 can be further arranged. 12. For the thirteenth drilling hole 3-13, the axial direction of the drilling hole is perpendicular to the free surface of the area, and the angle can be slightly adjusted according to the actual conditions on site, but not exceeding ±5°. All holes are drilled parallel to each other and the hole depth is consistent with the field depth.

Taking the five-hole layout plan for testing the surrounding rock 2-2 in the second area as an example, in the first borehole 3-1, the second borehole 3-2, the third borehole 3-3, and the fourth borehole 3-4 , The fifth borehole 3-5 installs the digital borehole camera probe 4 sequentially, advances gradually along the hole depth direction, and acquires image information of the entire borehole. After the test is completed, in all boreholes, including the first borehole 3-1, the second borehole 3-2, the third borehole 3-3, the fourth borehole 3-4, the fifth borehole 3- 5 Install the casing, and drill adjacent holes (including 8 groups, respectively the combination of the first hole 3-1 and the second hole 3-2, the combination of the second hole 3-2 and the third hole 3-3 , the combination of the third borehole 3-3 and the fourth borehole 3-4, the combination of the fourth borehole 3-4 and the first borehole 3-1, the combination of the first borehole 3-1 and the fifth borehole 3-5 Combination, the combination of the second borehole 3-2 and the fifth borehole 3-5, the combination of the third borehole 3-3 and the fifth borehole 3-5, the fourth borehole 3-4 and the fifth borehole 3- 5 combination,) Embed cross-hole ultrasonic test probe 5-1, cross-hole ultrasonic test probe 5-2, advance slowly synchronously, to obtain the propagation characteristics of sound waves in the surrounding rock between holes. Repeat this test at different times to obtain sound waves in the first borehole 3-1, the second borehole 3-2, the third borehole 3-3, the fourth borehole 3-4, and the fifth borehole at different times. Propagation characteristics between holes 3-5.

B. Analyze the borehole image information, and obtain the structure plane of the first borehole 3-1, the second borehole 3-2, the third borehole 3-3, the fourth borehole 3-4, and the fifth borehole 3-5 Occurrence, trace length, gap width and filling information, compare the similarity of the occurrence, trace length and gap width of adjacent boreholes, and combine the filling information to comprehensively judge whether a certain structural plane of adjacent boreholes is similar. If they are similar, extend or connect the structural planes of the drilled holes to obtain information on the structural planes between the holes. Furthermore, the spatial distribution characteristics of the volumetric joint number Jv of the surrounding rock structure in the roadway area are obtained through the statistical analysis of all boreholes and structural plane information between the holes in the area.

C. According to the wave velocity and attenuation characteristics of the sound wave propagating between the holes in different times, the change law of the regional surrounding rock integrity index Kv of the surrounding rock between the holes is obtained with time; the integrity index Kv of the surrounding rock between the holes is used as a boundary condition , back analysis of the spatial distribution characteristics of the regional surrounding rock integrity index Kv and its evolution over time.

D. Comparing comprehensively the surrounding rock volume joint number Jv of the surrounding rock integrity index and the regional surrounding rock integrity index Kv, the surrounding rock volume joint number Jv of the regional surrounding rock obtained through the borehole camera is used as the initial condition of the surrounding rock integrity, The evolution characteristics of the regional surrounding rock integrity index Kv obtained by the cross-hole ultrasonic test are used as the dynamic conditions of the surrounding rock integrity evolution to obtain the evolution process of the regional surrounding rock structure in the deep coal mine roadway.

Example 2:

This example detects the surrounding rock structure in the deep roadway area of a coal mine with a buried depth of -850m. The test area and drilling layout are shown in Figure 6, and the test excavated roadway 1-1 has a diameter of 4.50×3.45m. The specific methods and steps are as follows:

A. Select the second area 2-2 of the excavated roadway 1-1 as the area to be tested. The size of the area is 2×1×25m (width×height×depth), and the lower edge of the area is located 0.5m above the floor. Since the selected detection area is small, five boreholes are arranged at the boundary and center of the area, namely the first borehole 3-1, the second borehole 3-2, the third borehole 3-3, and the fourth borehole 3-4. The fifth drilling hole 3-5 has a diameter of 130mm, a downward slope of 2°, and a depth of 25m. In the first borehole 3-1, the second borehole 3-2, the third borehole 3-3, the fourth borehole 3-4, and the fifth borehole 3-5, install and push the digital borehole camera probe 4 sequentially , to collect borehole image information, as shown in Figure 7. After that, install in the first borehole 3-1, the second borehole 3-2, the third borehole 3-3, the fourth borehole 3-4, and the fifth borehole 3-5 for cross-hole ultrasonic testing The steel casing to the bottom of the borehole, the bottom of the steel casing is sealed, and then grouting makes the gap between the steel casing and the surrounding rock of the drilling hole filled and dense. In adjacent boreholes (including 8 groups, respectively the combination of the first borehole 3-1 and the second borehole 3-2, the combination of the second borehole 3-2 and the third borehole 3-3, the combination of the third borehole The combination of 3-3 and the fourth hole 3-4, the combination of the fourth hole 3-4 and the first hole 3-1, the combination of the first hole 3-1 and the fifth hole 3-5, the second hole combination of hole 3-2 and fifth hole 3-5, combination of third hole 3-3 and fifth hole 3-5, combination of fourth hole 3-4 and fifth hole 3-5,) Bury the cross-hole ultrasonic test probe 5-1 and the cross-hole ultrasonic test probe 5-2, advance synchronously and slowly to obtain the propagation speed and attenuation characteristics of the sound wave in the surrounding rock between the holes, as shown in Figure 8.

B. Cross-hole correlation based on the structural plane information of the first borehole 3-1, the second borehole 3-2, the third borehole 3-3, the fourth borehole 3-4, and the fifth borehole 3-5 Analysis to obtain the spatial distribution characteristics of the surrounding rock volume joint number Jv of the surrounding rock structure in the roadway area, as shown in Figure 9. Based on the cross-hole ultrasonic test results, the spatial distribution characteristics of roadway surrounding rock integrity index and its evolution over time are shown in Figure 10.

C. Based on the evolution characteristics of the surrounding rock volume joint number Jv and the regional surrounding rock integrity index Kv of the regional surrounding rock, the evolution process of the regional surrounding rock structure of the deep coal mine roadway is obtained, as shown in Figure 11.

According to the detection and analysis results of the surrounding rock structure in the region, it was found that the integrity of the surrounding rock near the roadway was relatively poor after excavation, and gradually expanded to the depth, and the evolution of the integrity of the surrounding rock did not enter a stable state. Meanwhile, the surface displacement monitoring results also showed the same result. Therefore, the test section was strengthened by shallow hole grouting + deep hole grouting + high-strength prestressed anchor cable + re-sprayed layer as secondary support. Afterwards, the test results showed that the integrity of the surrounding rock increased by 15% to 30% (as shown in Figure 12), and the evolution of the integrity of the surrounding rock gradually entered a stable state.

Claims (1)

1. be applicable to a detection analysis method for deep tunnel region, colliery surrounding rock structure, the steps include:

(1) in colliery deep laneway surrounding rock region to be measured, testing bore holes is arranged, boring lays respectively at zone boundary to be measured and regional center place, be parallel to each other between boring, hole depth is consistent with regional depth, for each boring, install successively in hole and push digital borehole camera probe, gather borehole image information, afterwards, adjacent boring combination of two, installs ultrasound probe header, carries out across hole ultrasonic investigation, by the repeated test in different time, obtain the propagation characteristic Evolution in time of sound wave country rock between hole;

(2) according to single hole arrangements surface information, carry out across hole association analysis, judge the similarity in adjacent hole structure face, extend or be communicated with hole structure face, the structural plane feature of country rock between acquisition pores, by the statistical study to surrounding rock structure surface information between all drilled hole in region and hole, obtain the spatial distribution characteristic of the country rock volume joint number Jv of region, tunnel surrounding rock structure;

(3) Acoustic Wave Propagation of adjacent boring in region is utilized to be characterized as boundary condition, the propagation characteristic of inverting sound wave in the country rock of whole region, the Perfection Index of analyzed area country rock, obtains spatial distribution characteristic and the Evolution in time of region rock integrity index Kv;

(4) Comprehensive Correlation rock integrity index country rock volume joint number Jv and region rock integrity index Kv, using the volume joint number Jv of region surrounding rock structure as the starting condition of rock integrity, the Evolution of region rock integrity index Kv is the dynamic condition of rock integrity, obtains the evolutionary process of region surrounding rock structure integrality.