桂林岩溶地面塌陷区土体崩解及影响因素分析

Soil Slaking Studies on Samples from Guilin Karst Terrain

为探索土层崩解速度及其影响因素,进行了原状土样自由崩解试验,分析得知土体的崩解是多种因素共同作用下的结果,土体的崩解速率与土的含水量、孔隙比、容重、渗透系数、水的波动频率有着密切的联系。前四项属于土体的特性指标,是自然形成的,一般只与土的物质成分、形成条件和所处的环境有关,受人为因素影响较弱。水的波动频率既与自然因素有关,更多的是受人类活动的影响,尤其是抽排地下水及灌溉最为严重。这些人类活动会引起水位波动,并可以促进土体崩解脱落、速度加快,促进土洞的形成、发展和塌陷的产生。

The free slaking studies on the undisturbed soils were performed in order to investigate the rate of the soil slaking and its influence factors.Testing data indicate that the rate soil slaking is influenced by many factors,such as,moisture content,void ratio,unit weight,and coefficient of permeability as well as the frequency of the groundwater fluctuation.The first four items are the physical properties of the soil and they are related to the soil composition,formation conditions and its surrounding environment.These factors are rarely related to the human activities.The groundwater fluctuation frequency,however,are affected by the natural environments as well as by the human activities,especially,the groundwater extraction and the irrigation.Groundwater fluctuation will accelerate the soil slaking and increase the formation of soil cavities at the soil-karst rock interface,finally,increase the development of the sinkhole collapse.