深埋隧道围岩松动圈探测技术研究与数值模拟分析

Research on detection technology for deep tunnel surrounding rock loose circle and numerical simulation analysis

围岩松动圈支护理论已被工程界广泛认同和接受,如何准确快速地探测松动圈深度更好的为工程服务,成为大家所关注的问题。以新建兰新铁路大梁隧道现场试验为依托,对测试断面围岩松动圈深度采用单孔声波测试法、地质雷达法进行探测,结合现场地应力及岩体物理力学参数实测结果进行数值模拟分析可知,以单孔声波测试法结果为基准,地质雷达测试结果与声波法测试结果基本一致,在围岩含水区域测试结果存在一定偏差,地质雷达发出的电磁波对含水区域比较敏感,发射和接收干扰较大,但地质雷达作为一种快速、无损的检测方法应该得到大力推广应用。由于数值计算时没有考虑爆破对围岩松动圈的影响,其计算结果与声波法探测结果相比偏小,但是两者的变化趋势基本上是一致的。数值计算应以现场地应力及岩体物理力学参数测试结果为依据,使计算结果更加真实,更好地为工程决策服务。

Surrounding rock loose circle support theory has been widely recognized and accepted by engineers, how accurate and fast detection loose circle depth better for engineering services become all issues of concern, the new Lan-xin railway girder tunnel based on field test, the test section of surrounding rock loose circle depth by single-hole sonic test method, the ground penetration radar(GPR) for detection and combining with the ground stress and physical and mechanical parameters of rock mass according to the result of the benchmark for the numerical simulation analysis shows that with single span acoustic test results for reference, GPR test results and acoustic method test results are basically the same, in the surrounding rock water area test results in some deviation, geological radar emit electromagnetic fields to water area is relatively sensitive, transmit and receive interference is bigger, but the geological radar as a rapid and nondestructive detection method should be strongly applied: Due to the numerical calculation of surrounding rock loose blasting without considering the influence of the circle, the calculation results are slightly smaller that ones obtained by the acoustic detection, but the trend is basically consistent. Numerical calculation should be based on the physico-mechanical parameters of rock mass stress and according to the test results, so as to make the results of calculation more real and better for the decision of project service.