基于地电场响应的地裂缝模拟试验

在应用网络并行电法技术的基础上,建立有基底潜山的物理模型,对注水条件下模型土体开裂过程中的地电场响应进行测量。试验结果表明,土体中电位、电流和电阻率的变化与土体含水量密切相关,随着土体中含水量的改变,自然电位、一次场电位、激励电流和视电阻率发生急剧变化;网络分布式并行电法反演信息表明在视电阻率曲率值较大位置容易产生不均匀沉降和裂缝,不均匀沉降的程度越大,地裂缝的长度、宽度、深度也越大。

Simulation Test of Ground Fissures Based on Geoelectric Field Response

With development of the national economy,groundwater resources have been over-exploited in many areas of the country,which has led to serious problems in land settlement.Uneven settlement has induced many ground fissures,resulting in serious environmental problems and considerable economic loss.It is therefore extremely important to conduct studies on the three-dimensional geological structure of uneven settlement and ground fissures.In this paper,a network parallel electrical prospecting system is used with a physical model of a basement buried within a hill,to determine and measure the response of the geoelectric field during the process of soil cracking under the condition of water injection.Results show that changes in electric potential,current,and resistivity in the soil are closely related to water content,together with changes in the soil water content,electric potential,excitation potential,excitation current,and apparent resistivity change sharply.When water flows through the soil,the spontaneous potential,primary field potential,and exciting current rise quickly,but apparent resistivity sharply decreases.In addition,when apparent resistivity is large,soil deformation is also large,and there is danger of the development of ground fissures.Monitoring of electrical parameters can thus be used to warn of impending disasters.The inversion information obtained from the network parallel electrical prospecting system in this experiment shows that it is easy to induce uneven settlement and cracks at points of large curvature.The greater the degree of uneven settlement,the greater the length,width,and depth of the crack.The use of a network parallel electrical prospecting system for determining ground fissures is a novel idea that produces good results,and can be used as a reference in future research or to provide a new method and perspective for predicting geological disasters.