Research On Karst Collapse Stability Evaluation And Management Of New Hualian Plaza In Tang Shan

Karst is a world topic,many countries in urban development and engineering construction involving this problem more.China is a vast territory,the territory is vast,the distribution of karst landform is very wide,the distribution area is relatively large,the area is about 90 million km2.Located in the city of Tangshan,the central distribution of the city is karst,and its overburden thickness varies from 30.0.Geotechnical engineering investigation,karst investigation,foundation design,foundation treatment,building construction and other work in Tangshan area,because of underground broken bedrock,complex geological conditions,underground complex karst development space and other difficult geological problems,make construction difficult to increase greatly.The difficulty of engineering construction in such complex geological conditions is that it is not only construction difficulty,construction period and construction cost,but also face various unpredictable risks,in addition to the possibility to encounter karst cave collapse,ground karst collapse and so on a series of problems,so the importance of engineering geological survey in the karst area is self-evident.Because every detail of the mistakes can cause catastrophic consequences and irreversible losses,it is necessary to study the karst engineering survey,the stability of karst foundation,the comprehensive treatment of karst geological disasters.Based on the project investigation of new hualian square in Tangshan city,the karst collapse occurred in the area,and then according to the geological conditions,we choose to use karst exploration,seismic reflection,passive source surface wave exploration,electromagnetic wave CT and other test methods,analyze and evaluate the foundation stability of karst collapse,and put forward the treatment plan for the karst geological disaster in this area.The main results are as follows:(1)Through the field survey of karst geology and surrounding environment,the regional geological information of Tangshan area is grasped,and a large number ofkarst collapse parameter data and geological basic data are obtained,which provide reliable analysis basis for the later project research.(2)Relying on the Tangshan new hualian square project,the underground karst collapse occurred in the field area,using seismic reflection wave method,passive source surface wave exploration method and electromagnetic wave CT method to preliminarily determine the karst collapse position of the underground karst in Tangshan new hualian square,which is unstable.(3)Based on geophysical prospecting results and stability analysis,the method of grouting is adopted in the unstable region of karst collapse in the field area.(4)The method of drilling core pulling and seismic image is adopted to detect the grouting.Visible karst,fissure position has been injected into the slurry,the core sample is dense,no hole,no leakage,drilling,drill pipe sticking and other phenomena,the borehole TV shows that the hole wall is complete,cracks and karst caves have been filled with cement slurry to show that the karst after treatment,high filling,strong rate.The grouting effect is achieved and the field is stable.