【作者】 李根；

【导师】 韩同春；

【作者基本信息】 浙江大学 ， 建筑与工程（专业学位）， 2022， 硕士

【摘要】 统计和试验表明边坡失稳现象一般都是由降雨导致的,这在含裂隙边坡当中更为突出。裂隙的存在为降雨入渗提供了优势通道,导致降雨产生的径流部分进入到裂隙中,一方面这将增大裂隙处水头压力,裂隙处水头的增大将会导致土壤入渗强度的提高,同时由于裂隙本身具有一定的深度,这也将导致坡面水快速从地表流动到土壤深处,增大深部土壤的含水率。土壤的含水率增加会导致土壤基质吸力的削减进而使土壤的抗剪强度降低,对边坡整体的稳定性造成威胁。因此研究裂隙与径流之间的关系能更好的理解裂隙土边坡的失稳特点,这具有一定的学术意义和工程实用价值。本文查阅了国内外学者对地表径流方程的数值求解以及裂隙土坡降雨入渗数值模拟的相关文献,采用有限体积法耦合了地表径流方程和Richards方程,将裂隙蓄水现象引入到本文裂隙土坡的入渗稳定性分析当中。研究结果揭示了地表径流与土体裂隙之间的相互作用对裂隙土坡整体稳定性的影响。本文所研究的工作和成果主要有:(1)介绍了求解地表径流方程以及Richards入渗方程所采用的不同数值方法的相关文献,在此基础上对地表径流方程和Richards入渗方程应用具有整体质量守恒性的有限体积法求解,实现了地表径流和土壤入渗的耦合求解。通过将耦合模型的结果与在相同边界条件下用SEEP/W计算的结果进行对比,验证了耦合模型的有效性。(2)综合分析了前人通过数值模拟计算裂隙土坡案例的相关成果,针对前人在裂隙模拟上所做工作的局限性,通过考虑裂隙的形状,实现了地表径流条件下裂隙蓄水现象的数值模拟。(3)计算了地表径流条件下土坡坡脚和坡顶的入渗,结果显示由于坡面径流的影响导致坡脚处的入渗强度要高于坡顶处的入渗强度,同时计算了单裂隙土坡在考虑地表径流与不考虑地表径流条件下的裂隙位置处的入渗情况,计算结果表明裂隙蓄水作用显著提升了裂隙位置处的入渗强度。(4)进一步分析了考虑与不考虑径流条件下的多裂隙土坡的入渗稳定性,通过对比实验数据可知裂隙土坡的临界滑移面与裂隙位置有关,且边坡失稳方式为浅层滑移,同时根据不同工况下的安全系数随时间变化的结果可知,降雨径流作用显著地影响着多裂隙边坡的稳定性。因此在多裂隙边坡的稳定性分析中需要考虑降雨径流带来的影响。更多还原

【Abstract】 It is clearly stated in the statistics and tests that slope instability is mostly caused by the rainfall infiltration,which can be significantly seen in the cracked soil slope.As a result of the existence of fractures lead to the emergence of rainfall runoff part into the fractures itself,this will increase water head of fractures,for which the increase of intensity of soil infiltration will be increased,and because the fracture itself has a certain depth,it will also lead to rapid water flow to the depths of soil slope,increasing the moisture content of soil.The increase of soil moisture content will lead to the reduction of soil matric suction and thus reduce the shear strength of soil,which will threaten the stability of slope as a whole.Thus,the characteristics of cracked soil slope instability can be seen through interaction between surface runoff and soil cracks,which can have a certain academic significance and engineering practical value.In this paper,numerical simulation of rainfall infiltration of cracked soil and surface runoff had been reviewed,and surface runoff equation and Richards equation were coupled by the finite volume method,and also,the phenomenon of fissure water storage was introduced into the cracked soil slope stability.According to the result,the influence of cracked soil slope stability is revealed by the interaction between surface runoff and soil cracks.The main work and achievements of this paper are as follows:(1)Various numerical methods to solve surface runoff equation and Richards equation were introduced in this paper,based on which all the equations mentioned were solved by finite volume method which has an overall moment and mass conservation,and the coupled solution of surface runoff and soil infiltration was realized.The results of the coupled model were compared with those calculated by SEEP/W under the same boundary conditions,and the validity of the coupled model was verified.(2)Limitations were found by analyzing the previous works of cracked soil slope,and phenomenon of fissure water ponding were simulated numerically by considering the geometry of soil cracks.(3)That infiltration intensity of slope toe is higher than that at the top of it under surface runoff condition can be seen from the result of calculation,and the infiltration intensity of the cracked soil slope is significantly improved by the fissure water ponding by comparing results of calculation with surface runoff to one without surface runoff.(4)The stability of multi-fissure slope was calculated with surface runoff and one without surface runoff condition,and the result implied that the location of critical slope surface was related with cracks,and also the characteristics of slope instability was shallow failure,and according to the change of safety factor over time under two different situation,the fissured soil slope stability is significantly influenced by rainfall and runoff.therefore,rainfall and runoff should be considered in the stability analysis of multi-fissure slope.更多还原