土质边坡在不同降雨强度下的渗流场分析
|
摘要
在FLAC~(3D)计算模型中利用FISH语言自编模块实时修改非饱和区单元的表观渗透张量以实现饱和—非饱和渗流分析,实时改变边界条件以考虑降雨入渗过程中的不定边界。以降雨强度和降雨历时为参数,并考虑地表径流形成的水膜对渗流场的影响,分析了不同降雨强度下饱和—非饱和均质土质边坡渗流场的分布规律。通过实例计算得出:降雨过程中,基质吸力变化范围主要集中于浅层地表,降雨强度越大,降雨历时越长,受降雨影响的范围越大;地表雨水容易达到的区域的基质吸力最先开始变化,且经历初始缓慢变化、加速变化和稳定不变三个阶段,雨强越大,基质吸力变化越快,最终稳定值越大;地表径流形成的不同厚度的水膜对暂态饱和区的影响显著;降雨停止后,随着坡体内孔隙水的消散,渗流场依然具有很明显的变化。研究成果与已有结论进行定性对比,验证了自编模块适用于降雨入渗条件下饱和—非饱和土质边坡的渗流计算,为利用FLAC~(3D)解决非饱和土体的流—固耦合问题开拓了一种新思路。
A newly self-program module was developed based on FISH language with FLAC~(3 D) to analyse saturated-unsaturated seepage by modifying the apparent permeability tensor of unsaturated zone in time and to consider indefinite boundary of rainfall infiltration by changing boundary conditions at each calculation step. Considering the influence of water film induced by surface runoff on seepage field and combining with the two parameters of rainfall intensity and duration, the distribution regularity of saturated-unsaturated seepage field was discussed. The results indicate that during the process of rainfall, the matric suction change is mainly found in the shallow surface. The greater the rainfall intensity and the longer the rainfall duration, the more region influenced by rainfall is; the matric suction of the zone where rainwater infiltration reaches easily will change firstly, and the change has three phases, i.e. initial slow change, accelerated change and stable change. The greater the rainfall intensity, the faster the matric suction changes and the grater the final stable value are; the different thickness water film induced by surface runoff have a significant effect on the transient saturation zone; after the rainfall stops, seepage field will change significantly with slope pore water dissipating. Compared with the existing results from others, the self-programmed module is proved suitable to calculate saturated-unsaturated seepage of soil slope during rainfall, and provides a new method to solve the fluid-solid coupled problem for unsaturated slope.
A newly self-program module was developed based on FISH language with FLAC~(3 D) to analyse saturated-unsaturated seepage by modifying the apparent permeability tensor of unsaturated zone in time and to consider indefinite boundary of rainfall infiltration by changing boundary conditions at each calculation step. Considering the influence of water film induced by surface runoff on seepage field and combining with the two parameters of rainfall intensity and duration, the distribution regularity of saturated-unsaturated seepage field was discussed. The results indicate that during the process of rainfall, the matric suction change is mainly found in the shallow surface. The greater the rainfall intensity and the longer the rainfall duration, the more region influenced by rainfall is; the matric suction of the zone where rainwater infiltration reaches easily will change firstly, and the change has three phases, i.e. initial slow change, accelerated change and stable change. The greater the rainfall intensity, the faster the matric suction changes and the grater the final stable value are; the different thickness water film induced by surface runoff have a significant effect on the transient saturation zone; after the rainfall stops, seepage field will change significantly with slope pore water dissipating. Compared with the existing results from others, the self-programmed module is proved suitable to calculate saturated-unsaturated seepage of soil slope during rainfall, and provides a new method to solve the fluid-solid coupled problem for unsaturated slope.
引文
[1] 田东方,郑宏,刘德福.考虑径流影响的滑坡降雨入渗二维有限元模拟及应用[J].岩土力学,2016,37(4):1179～1186.Tian Dongfang,Zheng Hong,Liu Defu.2D FEM numerical simulation of rainfall infiltration for landslide,with considering runoff effect and its application[J].Rock and Soil Mechanics,2016,37(4):1179～1186.(in Chinese)
[2] 刘春,邵晓航,李巍岳.顾及位移与雨量观测的降雨驱动滑坡稳定性分析[J].工程勘察,2018,46(2):46～52.Liu Chun,Shao Xiaohang,Li Weiyue.Xishancun landslide stability analysis by coupling GPS monitoring and rain fall observation[J].Geotechnical Investigation & Surveying,2018,46(2):46～52.(in Chinese)
[3] 戚国庆,黄润秋,速宝云等.岩质边坡降雨入渗过程的数值模拟[J].岩石力学与工程学报,2003,22(4):625～629.Qi Guoqing,Huang Runqiu,Su Baoyu et al.Numeric simulation on rainfall infiltration on rock slope[J].Chinese Journal of Rock Mechanics and Engineering,2003,22(4):625～629.(in Chinese)
[4] B.A.Schrefler,X.Zhan.A fully coupled model for water flow and airflow in deformable porous midea[J].Water Resource Research,1993,29(1):155～167.
[5] D.G弗雷德隆德,H.拉哈尔佐.陈仲颐等译.非饱和土土力学[M].北京:中国建筑工业出版社,1997.D.G Fredlund,H Rahardjo.Translated by Chen Zhongyi et al.Soil mechanics for unsaturated soils[M].Beijing:China Architecture and Building Press,1997.(in Chinese)
[6] 陈育民,徐鼎平.FLAC/FLAC3D基础与工程实例[M].北京:中国水利水电出版社,2013.Chen Yuming,Xu Dingpin.Foundation and example of FLAC/FLAC3D[M].Beijing:China Waterpower Press,2013.(in Chinese)
[7] 李毅,伍嘉,李坤.基于FLAC3D的饱和—非饱和渗流分析[J].岩土力学,2012,33(2):617～623.Li Yi,Wu Jia,Li Kun.Saturated-unsaturated seepage analysis based on FLAC3D[J].Rock and Soil Mechanics,2012,33(2):617～623.(in Chinese)
[8] 蒋中明,熊小虎,曾玲.基于FLAC3D平台的边坡非饱和降雨入渗分析[J].岩土力学,2014,35(3):855～862.Jiang Zhongming,Xiong Xiaohu,Zeng Ling.Unsaturated seepage analysis of slope under rainfall condition based on FLAC3D[J].Rock and Soil Mechanics,2014,35(3):855～862.(in Chinese)
[9] 包承纲,詹良通.非饱和土性状及其与工程问题的联系[J].岩土工程学报,2006,28(2):130～136.Bao Chenggang,Zhan Liangtong.Relationship between unsaturated soil behavior and engineering problems[J].Chinese Journal of Geotechnical Engineering,2006,28(2):130～136.(in Chinese)
[10] 谭新,陈善雄,杨明.降雨条件下土坡饱和—非饱和渗流分析[J].岩土力学,2003,24(3):381～385.Tan Xin,Chen Shanxiong,Yang Ming.Saturated-unsaturated seepage analysis of slope under rainfall[J].Rock and Soil Mechanics,2003,24(3):381～385.(in Chinese)
[11] Mein R G,Larson C L.Modeling infiltration during a steady rain[J].Water Resources Research,1973,9(2):384～394.
[12] 李兆平,张弥.考虑降雨入渗影响的非饱和土边坡瞬态安全系数研究[J].土木工程学报,2001,34(5):57～61.Li Zhaoping,Zhang Mi.Effects of rain infiltration on transient safety of unsaturated soil slope[J].China Civil Engineering Journal,2001,34(5):57～61.(in Chinese)
[13] S.E.Cho,S.R.Lee.Instability of unsaturated soil slopes due to infiltration[J].Computers and Geotechnics,2001,28,185～208.
[14] 钱纪芸,张嘎,张建民.降雨条件下土坡变形机制的离心模型试验研究[J].岩土力学,2011,32(2):398～402.Qian Jiyun,Zhang Ga,Zhang Jianmin.Centrifuge model tests for deformation mechanism of soil slope during rainfall[J].Rock and Soil Mechanics,2011,32(2):398～402.(in Chinese)
[15] 常士骠,张苏民,项勃等.工程地质手册[M].北京:中国建筑工业出版社,1992.Chang Shibiao,Zhang Suming,Xiang Bo et al.Manual of engineering geology[M].Beijing:China Architecture and Building Press,1992.(in Chinese)
[2] 刘春,邵晓航,李巍岳.顾及位移与雨量观测的降雨驱动滑坡稳定性分析[J].工程勘察,2018,46(2):46～52.Liu Chun,Shao Xiaohang,Li Weiyue.Xishancun landslide stability analysis by coupling GPS monitoring and rain fall observation[J].Geotechnical Investigation & Surveying,2018,46(2):46～52.(in Chinese)
[3] 戚国庆,黄润秋,速宝云等.岩质边坡降雨入渗过程的数值模拟[J].岩石力学与工程学报,2003,22(4):625～629.Qi Guoqing,Huang Runqiu,Su Baoyu et al.Numeric simulation on rainfall infiltration on rock slope[J].Chinese Journal of Rock Mechanics and Engineering,2003,22(4):625～629.(in Chinese)
[4] B.A.Schrefler,X.Zhan.A fully coupled model for water flow and airflow in deformable porous midea[J].Water Resource Research,1993,29(1):155～167.
[5] D.G弗雷德隆德,H.拉哈尔佐.陈仲颐等译.非饱和土土力学[M].北京:中国建筑工业出版社,1997.D.G Fredlund,H Rahardjo.Translated by Chen Zhongyi et al.Soil mechanics for unsaturated soils[M].Beijing:China Architecture and Building Press,1997.(in Chinese)
[6] 陈育民,徐鼎平.FLAC/FLAC3D基础与工程实例[M].北京:中国水利水电出版社,2013.Chen Yuming,Xu Dingpin.Foundation and example of FLAC/FLAC3D[M].Beijing:China Waterpower Press,2013.(in Chinese)
[7] 李毅,伍嘉,李坤.基于FLAC3D的饱和—非饱和渗流分析[J].岩土力学,2012,33(2):617～623.Li Yi,Wu Jia,Li Kun.Saturated-unsaturated seepage analysis based on FLAC3D[J].Rock and Soil Mechanics,2012,33(2):617～623.(in Chinese)
[8] 蒋中明,熊小虎,曾玲.基于FLAC3D平台的边坡非饱和降雨入渗分析[J].岩土力学,2014,35(3):855～862.Jiang Zhongming,Xiong Xiaohu,Zeng Ling.Unsaturated seepage analysis of slope under rainfall condition based on FLAC3D[J].Rock and Soil Mechanics,2014,35(3):855～862.(in Chinese)
[9] 包承纲,詹良通.非饱和土性状及其与工程问题的联系[J].岩土工程学报,2006,28(2):130～136.Bao Chenggang,Zhan Liangtong.Relationship between unsaturated soil behavior and engineering problems[J].Chinese Journal of Geotechnical Engineering,2006,28(2):130～136.(in Chinese)
[10] 谭新,陈善雄,杨明.降雨条件下土坡饱和—非饱和渗流分析[J].岩土力学,2003,24(3):381～385.Tan Xin,Chen Shanxiong,Yang Ming.Saturated-unsaturated seepage analysis of slope under rainfall[J].Rock and Soil Mechanics,2003,24(3):381～385.(in Chinese)
[11] Mein R G,Larson C L.Modeling infiltration during a steady rain[J].Water Resources Research,1973,9(2):384～394.
[12] 李兆平,张弥.考虑降雨入渗影响的非饱和土边坡瞬态安全系数研究[J].土木工程学报,2001,34(5):57～61.Li Zhaoping,Zhang Mi.Effects of rain infiltration on transient safety of unsaturated soil slope[J].China Civil Engineering Journal,2001,34(5):57～61.(in Chinese)
[13] S.E.Cho,S.R.Lee.Instability of unsaturated soil slopes due to infiltration[J].Computers and Geotechnics,2001,28,185～208.
[14] 钱纪芸,张嘎,张建民.降雨条件下土坡变形机制的离心模型试验研究[J].岩土力学,2011,32(2):398～402.Qian Jiyun,Zhang Ga,Zhang Jianmin.Centrifuge model tests for deformation mechanism of soil slope during rainfall[J].Rock and Soil Mechanics,2011,32(2):398～402.(in Chinese)
[15] 常士骠,张苏民,项勃等.工程地质手册[M].北京:中国建筑工业出版社,1992.Chang Shibiao,Zhang Suming,Xiang Bo et al.Manual of engineering geology[M].Beijing:China Architecture and Building Press,1992.(in Chinese)