岩溶塌陷灾害监测预报技术与方法初步研究——以桂林市柘木村岩溶塌陷监测为例

Preliminary study on the technology and method of sinkhole collapse monitoring and prediction——As an example of sinknole collapse monitoring station in Zhemu Villgae,Guilin City

我国可溶岩分布面积达365万km2,占国土面积的1/3以上,是世界上岩溶最发育的国家之一。近年来,随着岩溶区城市化建设的飞速发展,岩溶区土地资源、水资源和矿产资源开发的不断增强,由此而引发的岩溶塌陷问题日益突出,已成为岩溶区城市主要地质灾害,严重妨碍城市经济建设与发展。由于岩溶塌陷的产生在时间上具突发性,在空间上具隐蔽性,在机制上具复杂性。因此,被普遍认为难以采取地面常规监测手段,对塌陷进行监测预报。另一方面,试验研究表明,岩溶水气压力变化对塌陷具有触发作用,可以以此作为衡量塌陷发育的临界条件。这就意味着通过对岩溶管道系统的水(气)压力的动态变化进行观测,可以达到对塌陷进行预报的目的。论文以位于广西桂林柘木村的岩溶塌陷监测站为例,详细讨论这一技术方法。

Through the large-scale model experiment of sinkhole formation,it was recognized that the change of pressure in karst opening is the key factor to trigger sinkhole collapse in China.That means sinkhole formation ispredictable using long-term monitoring of the groundwater pressure in karst opening.In order to establish an ap-proach and methodology for forecast of sinkhole collapse accidents,supported by the national early warning pro-grams of geological hazards of China Geological Survey,the project of sinkhole collapse prediction has been im-plemented since2000.The study site is located at Zhemu in the south of Guilin City,where has been suffered from collapses since November11th,1997,and more than60sinkholes were formed.there The equipments were select-ed including vibrating wire piezometers,the data acquisition system,and ground penetrating rada.There are six-teen piezometers kept in karst fracture and the bottom of overburden soil to record the pressure dynamic.The paper introduces the geological setting of research site and the sinkhole me collapse chanism firstly,and then discusses the method to determine the criterion triggering sinkhole.And finally,the authors present the long-term monitoring system and the research results in detail.