浅埋红黏土隧洞围岩含水率迁移研究及地层结构反演分析

STUDY OF MOISTURE CONTENT MIGRATION OF RED CLAY AND STRATIGRAPHIC STRUCTURE INVERSION ANALYSIS IN SHALLOW BURIED TUNNEL

浅埋软土隧道围岩的含水率对围岩的力学性质有直接影响,对围岩的稳定性至关重要。以地质雷达对围岩中水较为敏感的特性为思路,从河南巩登高速公路隧道掌子面采集红黏土,压实土样并调节实验样品的含水率从10%至30%,并以多种频率的地质雷达波扫描测试,建立红黏土的含水率和地质雷达波速的关系,进而建立含水率与介电常数的关系。应用这一思路,通过连续多次监测,由地质雷达扫描数据得到围岩含水率分布,预测围岩的力学参数及其变化情况,揭示隧道开挖区域含水率分布及其力学参数随着开挖过程的进行而发生的迁移变化等规律,对隧道围岩稳定性做出快速量化评估。

In geotechnical engineering,the moisture content of shallow embedded soil directly affects mechanical property in the surrounding rocks and crucial important issue of the stability of tunnel. Based on the characteristics of ground penetrating radar（GPR） is sensitive to the water in soil,sampling red clay from tunnel face,adjusting the moisture content of experimental samples from 10% to 30%,and scanning it by variety of frequency of GPR. In consequence,a relationship of moisture content of red clay and the speed of GPR wave is set up. Through continuous monitoring for many times,the moisture content of surrounding rock are obtained by geological radar scanning,and the mechanical parameters as well as its changes related to the moisture content within the detection ranges are predicted. Therefore,moisture content distribution and mechanical parameters of tunnel excavation are revealed as the excavation process of changes occurring in the course of migration,and give a rapid quantitative assessment on the stability of tunnel.