In situ modified energy absorption/anti impact test of surrounding rock in a certain rockburst tunnel

　Project Category: Coal Mine Tunnel Protection Test

1. Project Overview

Rock burst refers to a dynamic phenomenon in which sudden failure occurs in the exposed rock mass in deep mining areas or zones with high tectonic stress during coal mine roadway excavation, releasing the energy of coal and rock mass in a violent manner. The massive collapse of coal and rock mass caused instantaneously by rock burst generates intense noise and air blast impact, which can crush and damage roadways and easily induce secondary disasters such as gas explosions. With the rapid increase of mining depth, rock burst disasters have presented a detrimental trend where "the faster the number of affected mines grows, the more severe the disaster becomes". Therefore, to prevent the occurrence of rock burst disasters, it is imperative to fully develop the anti-burst technology for coal mine roadway support.

Figure 1 Coal mine rockburst disaster　　

2. Service Content

• We need to provide on-site installation and testing of 16 dynamic earth pressure sensor points, as well as on-site data analysis services for the project owner.

• The earth pressure sensors provided for this project are required to measure the dynamic earth pressure data of roadways in ordinary coal mines and coal mines with modified surrounding rock under different working conditions, so as to analyze the dynamic response process of the tunnel surrounding rock and its support system under the impact dynamic action of the roof.

• The earth pressure sensor used in this project requires miniaturization in size to minimize interference and soil arching effects on the original site, with high-frequency response (response time ≤ 0.1ms), resolution ≤ 0.1kPa, impact resistance of ≥ 100 groups, and failure rate ≤ 5%.

• The instrument model provided for this project is ESP-II dynamic earth pressure sensor (customized), with the main parameters shown in Table 1.

3. Project Overview and Representative Data

(1) Experimental equipment

The experimental equipment used in this test is a two-dimensional solid-liquid coupling similar material simulation test platform.

(2) Sensor deployment and experimental model

The layout plan of ESP-II earth pressure sensor is shown in Figure 3.

(3)Representative experimental data

4. Service Evaluation

Our technical personnel provided on-site sensor deployment guidance, debugging of data acquisition instruments, dynamic earth pressure data analysis and data processing services throughout the project location. More importantly, the data recorded by DSP-I pore pressure sensors and ESP-II earth pressure sensors provided important information for coal mine tunnel protection research and received high praise from the user units.

User evaluation: The ESP-II micro dynamic earth pressure sensor not only has a miniaturized size, but also features high response accuracy, frequency response rate, high resolution, and resistance to strong vibration and impact, reaching the leading technical level of similar products in China.

References:

[1] Notice on Further Strengthening the Prevention and Control of Coal Mine Rockburst issued by the National Mining Safety Supervision Bureau (Mining Safety [2020] No. 1)  

[2] Investigation Report on the 2018 Shandong Energy Longkuang Group Shandong Longyun Coal Industry Co., Ltd. "10 · 20" Major Impact Ground Pressure Accident

[3] Wang Yonggang, Duan Jin, Lang Xuecong, Zhi Yuandong, Li Hongxing, Liu Hanbin Analysis and prevention suggestions for rockburst disasters in Datong coal mining area, Shanxi Province [J]. Mineral Exploration, 2020,11 (11): 2567-2572