Comprehensive geophysical prospecting technique in urban subway survey study and case analysis
In subway investigation,undesirable geological conditions such as karst,fracture,and soft soil are the main hidden dangers of the project,which seriously threaten the safety of the subsequent construction of the project.In addition to the conventional geological survey,it is necessary to adopt effective and suitable geophysical methods for the urban environment to improve the reliability and coverage of survey data.The urban environment is complex,the site conditions are limited,the interference of different physical properties is substantial,and the overall geophysical environment is harsh.Taking the survey of Xuzhou Metro Lines 4 and 5 as an example,this paper firstly evaluates the geophysical environment according to the specific site conditions;secondly,analyzes the technical adaptability of various geophysical methods,and proposes the best coupling of the site environment and technical methods;finally,summarizes the set of geophysical technology models with strong applica-bility and operability.The results of the comprehensive comparative analysis show that ①microtremor,transient electromag-netic,and other technologies can be used as the main ground geophysical means of urban areas and can preliminarily identify the location and occurrence characteristics of karst,fracture,and other geological bodies;②in the fine detection of karst,Interhole CT(electromagnetic wave)technology can further delineate the development scale and spatial location of karst;③Reasonable selection or combined application of ground and inter-pore geophysical exploration can provide geological data required for dif-ferent survey stages and different survey accuracy,and meet the needs of urban subways.
undesirable geological bodyXuzhou metro line 4 and 5subway explorationmircrotremortransient electromagneticseismic imageinterhole CT
国家科技期刊平台
NSTL
万方数据
维普
