跨孔地震CT在城市岩溶勘察中的应用

Application of Cross-hole Seismic CT to the Investigation of the Karst Caves in Foundation

在灰岩岩溶发育地区,城市重大工程建设的地基精细调查是建设基础设计和施工之前的重要环节之一。本文以广州某标志性建筑地基岩溶调查为例,利用已有的25个工程钻孔实施横、纵以及交叉测线的跨孔地震CT立体探测;并通过直达波层析成像技术揭示了研究区的三维速度结构,结合地质和工作钻孔查明了研究区的岩溶几何分布特征和规模,为后续溶洞处理和基础设计、施工提供充分依据。

In the limestone karst development area,the fine ground survey of major urban construction projects is one of the important links before the construction of basic design and construction.Taking the investigation of a landmark karst in Guangzhou as an example,this paper uses 25 existing engineering boreholes to perform cross-hole seismic CT stereoscopic detection of horizontal,vertical and cross-line surveys;and reveals the study area by direct-wave tomography.The three-dimensional velocity structure,combined with geological and working boreholes,identifies the karst geometric distribution characteristics and scale of the study area,providing a sufficient basis for subsequent cave treatment and foundation design and construction.