膨胀土边坡遛塌岩体力学性质衰变综合测试-《高速铁路技术》

文章信息/Info

Title:: Comprehensive Test of Mechanical Property Decay of Collapsed Rock Mass on Expansive Soil Slope

Author(s):: XIONG Zhaomei; The 2nd Engineering Co., Ltd of China Railway 17 Bureau Group Corporation, Xi’an 710043, China

摘要:: 膨胀土性质特殊，地区差异性明显，其易扰动的特性决定了对该类土体的评价方法多为原位测试。本文通过对云南省弥蒙铁路某膨胀土边坡遛塌段进行高密度电法、高密度面波的原位测试实验，分析了边坡土质分布特征，评价了该边坡的遛塌原因。结果表明，路基边坡遛塌的主要原因在于区域土体裂隙发育，结构性变化较弱，具体表现为土体电阻率的增大、横波波速的降低和弹性模量的减小。在降雨及工程扰动作用下，裂隙土内部物质组成、颗粒接触关系、孔隙性急剧变化，进而影响其物理力学特性，边坡稳定性降低而产生遛塌。高密度电法和高密度面波两种原位测试方法的结合适用于评价此类边坡岩体力学性质的衰变。本文研究成果对云南地区的膨胀土边坡防护具有指导意义。

Abstract:: Expansive soil has special properties and obvious regional differences, and it is easily disturbed, which determines that the evaluation method of this kind of soil is mostly in-situ test. In this paper, the in-situ tests with high-density electrical method and high-density surface wave method are carried out on the collapsed section of the expansive soil slope of Mile-Mengzi Railway in Yunnan Province, and the soil distribution characteristics of the slope are analyzed, and the reasons for the collapse of the slope are evaluated. The results show that the main reason of subgrade slope collapse lies in the development of regional soil fissures and weak structural changes, which are manifested in the increase of soil resistivity, the decrease of transverse wave velocity and the decrease of elastic modulus. Under the action of rainfall and engineering disturbance, the internal material composition, particle contact relationship and porosity of fissure soil change rapidly, which further affects its physical and mechanical properties, and the slope stability decreases, resulting in collapse. The combination of high-density electrical in-situ test method and high-density surface wave in-situ test method is suitable for evaluating the decay of mechanical properties of this kind of slope rock mass. The research results of this paper have guiding significance for expansive soil slope protection in Yunnan.