摘要
隔水帷幕渗漏是影响软土基坑稳定性的关键问题。针对隔水帷幕渗漏检测技术,开展了数值模拟和物理模型试验,深入研究了不同采集装置类型三维电阻率法和探地雷达法对渗漏异常的反映能力及在探测剖面上表现出来的异常特征,给出了判断帷幕是否渗漏和确定渗漏点位置的解释方法。结果表明:温纳装置、偶极装置和温纳-施龙贝格装置都能有效反映渗漏点的存在;降水后帷幕未发生渗漏时,与基坑外侧软土含水层相比,内侧软土层电阻率表现为高阻异常;帷幕渗漏后基坑内侧底部软土层电阻率降低,外侧电阻率升高,并呈现漏斗状异常,两侧低阻异常与帷幕的交叉点可正确指示渗漏点位置;帷幕发生渗漏后,基于基坑外侧的探地雷达探测剖面中会出现双曲型反射波同相轴,通过其顶点可确定渗漏点的位置。研究结果证实了两种地球物理手段开展软土基坑隔水帷幕渗漏检测的可行性。
The leakage of waterproof curtain is a serious problem for the stability of soft soil foundation pit. In respect of the leakage detection methods of waterproof curtain, the numerical simulation and indoor physical model test were performed to verify the ability to determine the leakage position of the three different arrays of 3D resistivity methods and GPR method, and to discuss the anomaly characteristics in detecting profile. At the same time, the judgment of whether the waterproof curtain leak or not and the interpretation method of leakage position were also made. The research shows that: the resistivity method can reflect the existence of leakage position effectively by Wennerarray, dipole dipole array, and Wenner-Sehlumberger array; it reveals high resistivity of soil inside foundation pit compared with that of outside the foundation pit without leakage of waterproof curtain; on the contrary, the resistivity will decrease at the bottom of saturation soil inside foundation pit, and it will increase outside the foundation pit and presents the funnel-shaped anomaly with leakage of waterproof curtain; using the cross point among the low resistivity anomalies and the curtain, we can also find the leakage position of waterproof curtain; in addition, there will show a hyperbolic reflection events in GPR detection profile after leakage of waterproof curtain, and we can also determine the leakage position through the vertex of the hyperbolic reflection. The results proved the feasibility of these two kinds of geophysical methods to carry out the leakage detection of waterproof curtain for soft soil foundation pit.
出处
《吉林大学学报(地球科学版)》
EI
CAS
CSCD
北大核心
2016年第1期295-302,共8页
Journal of Jilin University:Earth Science Edition
基金
岩土及地下工程教育部重点实验室开发基金项目(KLE-TJGE-B1107)
国家自然科学基金项目(41202204)~~
关键词
软土基坑
隔水帷幕
渗漏检测
电阻率
探地雷达
soft soil foundation pit
waterproof curtain
leakage detection
resistivity
GPR