广西黎塘岩溶塌陷监测

KARST COLLAPSE MONITORING IN LITANG,GUANGXI

黎塘是一个构造和岩溶发育的地区,抵抗岩溶地面塌陷的能力较低,在一定的条件触发下较容易产生岩溶地面塌陷。研究表明,岩溶地下水动力条件变化和湿化崩解作用是黎塘塌陷的主要影响和触发因素。本文采用现场实时监测岩溶地下水动态变化特征和室内试验相结合的方法,研究黎塘开发岩溶地下水的安全性。监测结果表明,I、II、III监测区的最大水压变化速度分别为0.048kPa/s、0.160kPa/s和0.007kPa/s,小于临界变化速度0.163kPa/s;最大水力坡降分别为0.717、1.052和0.566,小于临界坡降7.5。但是,I区满足临界水位埋深条件,而II区和III区则未满足临界水位埋深条件。因此,在目前的开采条件下,II区、III区处于相对稳定状态,I区处于不稳定状态。这说明在发生大规模塌陷后,当地政府从2000年起对地下水开发方案的调整是适当的。

Tectonic structure and karst are well-developed at Litang. The ability to withstand ground collapse is low. Ground easily collapses if it is triggered. The research proves that the groundwater＇s dynamic change and disintegration are the main factors for the collapse. Combining in-house experiment with real time monitoring of the groundwater dynamic change,this paper studied the security of the groundwater＇s exploitation. The result shows that the max speeds of hydraulic pressure change in monitoring region Ⅰ, Ⅱ and Ⅲ are 0. 048kPa/s, 0. 160kPa/s and 0. 007kPa/s respectively, which are lower than the critical change speed, and the max hydraulic gradients are 0. 717, 1. 052 and 0. 566 respectively, which are also lower than the critical hydraulic gradient. Monitoring region Ⅰsatisfies critical groundwater level, while monitoring regions Ⅱ and Ⅲ don＇t. So, regions Ⅱ and Ⅲ are stable and region Ⅰ is unstable at present exploitation condition. It is indicated that the present scheme of groundwater exploitation is right, which has been adjusted by local government since 2004 after massive collapses.