Technology Research On Real-time Monitoring For Treatment Effect Of Karst Geological Conditions In Beijing-Shanghai High-Speed Railway

The carst zone is mainly located in the Jinan-xuzhou section of the Beijing-Shanghai high-speed railway.The geological condition in the carst area is complex,and the carst has characteristics of irregular distribution and varied size.Carst detection is one of the most difficult and complex detection projects.There are several cases can not be accepted in the stress dispersion zone on the tip of pile,including rock mass free face,weak intercalated layers,fault zone and carst cave crack.During the investigation phase,the small drilling current used can not fully investigate the development of carst geology within the scope of the bridge pile cross-section.In the carst development layer,the pile hole construction would cause a lot of questions including slurry lose,drill falling,hole wall collapse and difficulties for pile forming. These questions can lead to the increase of the difficulty of pile construction,impact on the quality of bored piles construction and the safety of bridge.Hence,according to the carst geology of the Jinan-xuzhou section,it is very necessary to conduct the research of real-time monitor on geological treatment of the carst in Beijing-Shanghai High-Speed Railway.Based on the principle of seismic reflection wave,the typical bridge piers in Beijing-Shanghai high-speed railway are selected to explore the distribution of the carst area.During the experiment,mechanical vibrations due to the impact drill are regarded as a vibration source,and then to arrange a certain number of the detectors around the surface of pile to obtain the vibration from the process of pile construction;with the increase of the drilling depth,the mechanical vibration source is gradually moving to the deep,so that a number of seismic profiles at different depths can be formed to obtain the seismic data.Using the software ReflectSeis V1.0,a large number of seismic data are analyzed.Considering the design and construction materials,such as survey information on the bridge,working drawings and construction logs,the quantitative analysis and interpretation are outlined.The study shows that the seismic reflection technique can be efficiently used to real-timely explore the distribution of the carst at different depths during the pile and bridge construction.The purpose of real-time monitor on geological treatment of the carst in Beijing-Shanghai High-Speed Railway can be achieved.