基于车载重力测量平台的城市地下空洞快速探测

Rapid Detection of Urban Underground Cavity Based on Vehicle Gravity Measurement Platform

为了解决现有静态重力测量在城市地下空洞探测时存在工作难度大、效率低等问题,本文提出了基于车载重力测量平台的城市地下空洞快速探测方法。采用国产高精度捷联式重力仪SAG搭建车载移动重力测量平台,在长春卫星广场附近进行动态重力测量试验。首先对测得数据进行楼房干扰校正;之后采用基于传统极值点深度估计(depth from extreme points,DEXP)方法改进的比值DEXP方法进行重力异常数据深度成像;最后采用Tilt梯度法对位场数据进行边界识别。选取轻轨站附近两条测线进行研究,得出测线在700～1 300m区域附近存在负值异常,在800和1 000m附近最佳深度分别是24和28m,构造指数分别为0.18和0.06;经分析符合实际地下轻轨站空洞类型和所在范围,验证了车载移动平台重力测量在城市地下空洞探测中展开的可能性和有效性。

Gravity and its related measurement technology are widely used in underground cavity detection.The widely used static gravity survey has many problems such as difficulty in work and low efficiency when used for urban gravity detection.Although the dynamic gravity measurement based on mobile platform is widely applied in the field of sea and space,it is seldom used in underground cavity detection.In view of the shortages of the static gravity measurement method,a rapid detection method of urban underground cavity based on vehicle borne gravity measurement platform is proposed.In this study,a vehicle mobile gravity measurement platform was built by using domestic high precision strapdown gravimeter SAG,which was tested near Changchun Satellite Square.First of all,the measurement data were corrected to void the building interference;and then,the gravity anomaly data were measured with ratio DEXP(depth from extrme points);and finally,the tilt gradient method was used to identify the site boundary.The location of underground light rail station was determined,by which the feasibility and effectiveness of vehicle mounted platform gravity measurement in urban underground cavity detection are verified.