穿层巷道围岩松动圈范围测试及演化规律研究

    Study on the range test and evolution law of surrounding rock loose circle in cross-layer roadway

    • 摘要: 为探究穿层巷道围岩松动圈发育扩展规律,本文以淮北青东七采区回风上山为背景,采用理论分析、室内试验、数值模拟和现场实测方法研究巷道围岩松动圈发育扩展特征,提出光纤测试松动圈发育特征的相似模拟方法。结果表明:基于Mohr-Coulomb准则计算巷道围岩为泥岩、砂质泥岩、细砂岩和粉砂岩时,松动圈半径分别为1.72R0、1.65R0、1.41R0和1.42R0,巷道松动圈发育范围与围岩强度呈负相关;相似模拟试验显示巷道断面破坏范围与应力呈正相关,高应力下断面易破坏且裂隙发育范围近似半圆形;DIC数字散斑结果显示在巷道周边围岩位移呈梯度分布,围岩松动圈范围为巷道周边2 m围岩位移分界区域;分布式光纤监测显示深入围岩过程中产生两个应变突变拐点,第一应变突变点位置为围岩松动圈范围,第二应变突变点为围岩塑性区范围,围岩松动圈范围在梯度应力下由1.24 m发育至1.84 m,应力升高导致松动圈发育范围扩大,围岩稳定性逐渐降低;数值模拟结果显示穿层巷道开挖松动圈发育范围为0.62~1.86 m,相邻围岩共同决定松动圈扩展范围;现场地质雷达实测从距掘进工作面10 m至200 m,底板松动圈范围由1.45 m发育至1.95 m。相似模拟实验中分布式光纤监测松动圈方法,与其他方法测试结果吻合,可为巷道松动圈测试及围岩稳定性控制提供依据。

       

      Abstract: In order to explore the development and expansion law of surrounding rock loose circle in cross-layer roadway, this paper takes the return air uphill in Qingdong No.7 mining area of Huaibei as the background, the development and expansion characteristics of surrounding rock loose circle in roadway are studied by theoretical analysis, laboratory test, numerical simulation and field measurement, and a similar simulation method for testing the development characteristics of loose circle by optical fiber is proposed. The results show that when the surrounding rock of roadway is mudstone, sandy mudstone, fine sandstone and siltstone based on Mohr-Coulomb criterion, the radius of loose circle is 1.72R0, 1.65R0, 1.41R0 and 1.42R0, respectively. The development range of loose circle is negatively correlated with the strength of surrounding rock. The similar simulation test shows that the failure range of the roadway section is positively correlated with the stress. Under high stress, the section is easy to be destroyed and the fracture development range is approximately semi-circular. The results of DIC digital speckle show that the displacement of surrounding rock around the roadway is gradient distribution, and the range of surrounding rock loose circle is 2 m surrounding rock displacement boundary area around the roadway. Distributed optical fiber monitoring shows that there are two strain mutation inflection points in the process of entering the surrounding rock. The first strain mutation point is the range of surrounding rock loose circle, and the second strain mutation point is the range of surrounding rock plastic zone. The range of surrounding rock loose circle develops from 1.24 m to 1.84 m under gradient stress. The increase of stress leads to the expansion of the development range of loose circle and the gradual decrease of surrounding rock stability. The numerical simulation results show that the development range of the excavation loose circle of the cross-layer roadway is 0.62-1.86 m, and the expansion range of the loose circle is determined by the adjacent surrounding rock. The field geological radar is measured from 10 m to 200 m from the working face, and the range of the floor loose circle is developed from 1.45 m to 1.95 m. The method of distributed optical fiber monitoring loose circle in similar simulation experiment is consistent with the test results of other methods, which can provide the basis for the test of roadway loose circle and the stability control of surrounding rock.

       

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