桂林市西城区地下水活动与岩溶塌陷的关系

地下水活动是岩塌陷产生的基本条件之一，大气降雨、人工开采和灌溉渠道渗漏是影响地下水动态变化的主要因素。地下水位频繁的升降一是改变了上覆土体的状态和强度，促进土体崩落；二是引起地下岩溶及土洞空腔内的正负压力交替变化，使周转岩土体失稳，而导致塌陷。地下水位波动频度愈高，地面塌陷易产生；在地下水强径流带，塌陷分布料为密集。人为抽取地下水改变了地下水天然流场，形成水位下降漏斗及强径流带，并使水动力条件突变

THE RELATIONSHIP BETWEEN GROUNDWATER ACTIVITY AND KARSTIC COLLAPSE IN THE WESTERN REGIONS OF GUILIN

Groundwater activity is a basic forming condition of karstic collapse. Meteoric water, artificial exploitation and percolation for irrigation canals are the main influence factor of dynamic variation of groundwater.Frequent elevation and subsidence of groundwater not only change the state and strength of overlying soil mass and promote collapsing of soil mass, but also lead to alternate variation of normal and negative pressure in cavity of subjacent karst and soil cave and to unstability and collapsing of peripheral rock and soil mass. The greater the fluctuation frequence of underground water level, the easier to collapsing Earth's surface is. Collapse distribution centres on the intensive runoff zones. Artificial extracting of groundwater can change natural flow field of groundwater resulting in the formation of cryptodepression owing to water table and of intensive runoff zones, in the abrupt variation of hydraulic conditions and in collapsing. The more intesive the development strength of groundwater, the more the amount of collapses is.