研究目的:降雨是路基边坡失稳最主要的影响因素，其中降雨模式是主要的影响参数之一。本文基于二维饱和-非饱和渗流理论，利用数值计算的方法对后峰型、均布型、中峰型和前峰型4种降雨模式下路基边坡渗流场的变化规律进行研究。研究结论:(1)降雨强度和降雨持时对路肩处最大孔隙水压力umax和最大饱和深度Hsmax均影响显著；(2)渗透系数ks对Hsmax的影响存在一个敏感区，在敏感区之内，增加ks才能有效减小Hsmax和路基表层孔隙水压力，ks太小或太大均对路基稳定性不利；(3)中峰型和前峰型降雨模式下，路基边坡稳定性最不利时段受渗透系数影响显著，ks在敏感区之内和敏感区域之外较小一侧时，此时间段起点不受渗透系数影响，只与降雨模式有关，此时间段终点随ks的增大而提前；(4)后峰型降雨模式下路基边坡的稳定性最差，前峰型降雨模式下路基边坡的稳定性最好；(5)本文研究成果可为路基边坡防护与加固方案设计提供依据。
Abstract
Research purposes:Rainfall is one of the most important factors for subgrade slope failure, and rainfall patter is one of the most primary influence parameters. Based on the two-dimensional saturated-unsaturated seepage theory, numerical analyses are conducted to investigate the change rules of seepage field in subgrade slope subjected to rainfalls with four different patterns, i.e. delayed, uniform, central and advanced rainfall patterns.Research conclusions:(1) Both the maximum pore-water pressure umax and the maximum saturated depth Hsmax at shoulder are affected by rainfall intensity and rainfall duration observably. (2) There is a sensitive range of coefficient of permeability influencing on the maximum saturated depth, only within the sensitive range increasing coefficient of permeability could reduce Hsmax and subgrade surface pore-water pressure effectively. (3) Under central and advanced rainfall patterns, the most dangerous time stage of slope stability is obvious affected by coefficient of permeability, within the sensitive range and the less side outside the sensitive range, the starting point of the most dangerous time stage is not affected by coefficient of permeability, but the end time is advanced with coefficient of permeability increasing. (4) The stability of subgrade slope is the best under advanced rainfall pattern and the worst under delayed rainfall pattern. (5) The research results can provide basis and reference for slope protection and reinforcement design.
关键词
降雨模式 /
饱和-非饱和渗流 /
孔隙水压力 /
饱和深度 /
边坡稳定最不利时段
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Key words
rainfall pattern /
saturated-unsaturated seepage /
pore-water pressure /
saturated depth /
the most dangerous time stage of slope stability
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中图分类号：
TU43
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脚注
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基金
长江学者和创新团队发展计划(IRT1139)
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