南宁地铁4号线岩溶发育特征及处治技术

随着我国轨道交通建设的快速发展，城市地铁越来越多，修建过程中各种工程问题逐步显现。我国南方地区岩溶较为发育，给轨道交通的安全建设带来了一些工程难题，岩溶的处治技术成为近几年的研究热点。为了解决南宁地铁4号线岩溶带来的工程难题，通过地质勘察手段探明了岩溶分布规律，基于地质勘察资料分析了南宁地铁4号线岩溶发育规律，采用钻芯和室内试验确定了地层及溶洞的物理力学参数，结合有限元软件Midas GTS确定了溶洞与地铁车站、盾构隧道的安全距离，提出了岩溶区轨道交通溶洞处治范围及处治措施，并对溶洞处治区域进行取芯，通过室内试验研究了岩溶处治效果。研究结果表明，南宁地铁4号线岩溶总体上中等发育；车站区域溶洞基本上分布于底板下10m范围内，盾构隧道区域溶洞基本位于底板以及底板以下10m范围内；不同位置不同尺寸的溶洞塑性区不同，溶洞洞高越大塑性区越大，需要的安全距离越大；采用注浆加固方案是合理的，检测结果验证了其合理性。可为岩溶区地铁车站及盾构隧道溶洞处治提供参考。

Study on Karst Development Characteristics and Classification Treatment Technology of Nanning Metro Line 4

With the rapid development of China''s rail transit construction, there are more and more urban subways, and various engineering problems appear gradually in the construction process. Karst is relatively developed in southern China, which brings some engineering problems to the safety construction of rail transit. Karst treatment technology has become a research hotspot in recent years. In order to solve the engineering problems caused by the karst of Nanning Metro Line 4, the distribution law of karst is proved by means of geological survey. Based on the geological survey data, the karst development law of Nanning Metro Line 4 is analyzed. The physical and mechanical parameters of stratum and karst cave are determined by core drilling and laboratory test. Combined with the finite element software MIDAS, the karst development law of Nanning Metro Line 4 is analyzed GTS determines the safe distance between karst cave and subway station and shield tunnel, puts forward the treatment scope and measures of karst cave for rail transit in karst area, and core the treatment area of karst cave, and studies the treatment effect of karst cave through indoor test. The research results show that the karst of Nanning Metro Line 4 is generally moderately developed; the karst caves in the station area are basically distributed within 10m below the floor, and the karst caves in the shield tunnel area are basically located within 10m below the floor and below the floor. The results show that the plastic zone is different in different positions and sizes, the higher the cave height is, the larger the plastic zone is, and the greater the safety distance is needed. The grouting reinforcement scheme is reasonable, and the detection results verify its rationality. It can provide reference for the treatment of subway station and shield tunnel in karst area.