广清高速公路改扩建工程岩溶塌陷主要影响因素分析

岩溶塌陷对工程建设的影响不容小视。为了研究广清高速公路改扩建工程中影响岩溶塌陷的两个主要因素冲击荷载作用和地下水下降对塌陷的影响程度，在资料收集和现场调研的基础上，统计工程区12处岩溶塌陷的基本情况，总结塌陷特征并分析影响塌陷的主要因素，建立与实际覆盖层结构相符的塌陷地质模型-砂土+粉质黏土+灰岩地质模型。根据极限平衡理论，分别在冲击荷载和水位下降两种力学作用下对塌陷地质模型进行稳定性计算。通过计算得出，最大冲击荷载的作用在一定程度上会影响覆盖层的稳定性，但不是导致地面塌陷的主要因素，而地下水位下降对工程区岩溶塌陷起到了决定性的作用。通过进一步分析水位下降对塌陷的影响程度，确定水位降幅4m为警戒值， 6m为危险值，为保证施工的安全性提供一定的理论依据。

ANALYSIS OF THE MAIN FACTORS INFLUENCE ON KARST COLLAPSE IN HIGH-SPEED OF GUANGZHOU TO QINGYUAN

The problems of karst collapse can't be overlooked to engineering construction. The paper studies the extent of the karst collapse degree of two main factors(impact load and underground water) in high-speed of Guangzhou to Qingyuan. Based on data collection and field research, it concludes 12 points' basic information of karst collapse in research area, and sum up the characters of collapses and main effective factors. Besides, it sets up the geological model of sandy soil silty clay limestone,which conforms with the actual structure of overburden. In addition, it calculates the stability coefficient of overburden under two conditions using the limit equilibrium theory. It turns out the maximum impact loads.