赤水河段公路堆积体力学特性及致灾机理研究

Research on Mechanical Characteristics and Disaster Causing Mechanism of Highway Accumulation Body in Chishui River Reach

针对汛期蓉遵高速土城至赤水段路基地质灾害多发的问题,以K347滑坡为典型实例,通过工程勘察、现场试验、室内试验及数值模拟等手段,查明研究区工程地质条件及滑坡基本特征,掌握堆积体在降雨及干湿循环作用下力学变化特征,总结在降雨及河水位升降影响下的坡体稳定性变化规律。结果表明:含水率的升高及干湿循环次数的增加会导致土体强度发生不同程度的衰减;降雨及河水位升降会引起坡体内部渗流场发生变化,从而影响坡体稳定性;在区域环境长期影响下土体强度持续衰减是滑坡发生的内因,2020年7月初的暴雨导致坡体内部渗流作用达到极值则是滑坡发生的诱因。此类堆积体滑坡在土城至赤水段具有显著代表性,通过该研究可为此类滑坡的防治提供科学支撑。

In regard with the frequent occurrence of geological disasters in the roadbed of the Tucheng to Chishui Section of the Chengdu-Zunyi Expressway during the flood season,taking K347 landslide as a typical example,by means of engineering survey,on-site test,indoor test and numerical simulation,the engineering geological conditions and basic characteristics of landslides in the study area are identified,and the mechanical changes of the accumulation under rainfall and dry wet cycles are made clear,and the stability changes of the slope under the influence of rainfall and river water level fluctuations are summarized.The results indicate that the increase of moisture content and the number of dry wet cycles can lead to varying degrees of attenuation in soil strength;rainfall and river water level fluctuations can cause changes in the internal seepage field of the slope,thereby affecting the stability of the slope.Under the long-term influence of regional environment,the continuous decline of soil strength is the internal cause of landslide,and the extreme seepage in the slope caused by the rainstorm in early July is the inducement of landslide.This type of accumulation landslide is quite typical in the section from Tucheng to Chishui,and this study is expected to provide scientific support for the prevention and control of such landslides.