基于指数型的浅层滑坡非积水降雨入渗模型研究
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摘要
降雨诱发浅层滑坡稳定性评价的前提是计算边坡的湿润锋深度,目前较为常用的计算方法是基于改进的Mein-Larson降雨入渗模型,但该模型假定斜坡土体初始含水率均匀分布,实际上斜坡土体初始含水率分布是不均匀的,其表现出越靠近地下水位土体含水率越高的规律。为了体现这一实际情况,提出一种指数型的土体初始含水率分布函数,对传统的非积水降雨入渗模型进行了改进,并通过有限元数值分析对土体初始含水率分布函数和改进的模型进行了验证。结果表明:模型计算解与数值解较为接近,说明改进的非积水降雨入渗模型具有一定的适用性。
The calculation of wetting front is the premise of stability evaluation for shallow landslides induced by rainfall,and the prevalent computing methods by far based on the improved Mein-Larson model for rainfall infiltration.The model assumes that the water content of the slope soil is constant in the conduction zone.However,it is actually uneven and becomes higher as the depth gradually approaches to the water table.To reflect the actual situation,this paper proposes an exponential distribution function of initial water content,which improves the traditional model of rainfall infiltration for non-ponding conditions.The paper also verifies the function and the improved model by the numerical analysis of finite elements.The results indicate that the calculation solutions are close to the numerical solutions,and thus proves the applicability of the improved model.
The calculation of wetting front is the premise of stability evaluation for shallow landslides induced by rainfall,and the prevalent computing methods by far based on the improved Mein-Larson model for rainfall infiltration.The model assumes that the water content of the slope soil is constant in the conduction zone.However,it is actually uneven and becomes higher as the depth gradually approaches to the water table.To reflect the actual situation,this paper proposes an exponential distribution function of initial water content,which improves the traditional model of rainfall infiltration for non-ponding conditions.The paper also verifies the function and the improved model by the numerical analysis of finite elements.The results indicate that the calculation solutions are close to the numerical solutions,and thus proves the applicability of the improved model.
引文
[1]刘新喜,晏鄂川,王鹏飞,等.滑坡稳定性评价的非线性方法[J].中国安全科学学报,2003,13(1):34-36.
[2]戚国庆.降雨诱发滑坡机理及其评价方法研究——非饱和土力学理论在降雨型滑坡研究中的应用[D].成都:成都理工大学,2004.
[3]Polemio M,Petrucci O.Rainfall as a landslide triggering factor:An overview of recent international research[M]//Bromhead E,Dixon N,Ibsen M L.Landslides in Research,Theory and Practice.London:Thomas Telford Ltd.,2000:1219-1226.
[4]Tsai T,Chiang S.Modeling of layered infinite slope failure triggered by rainfall[J].Environmental Earth Sciences,2013,68(5):1429-1434.
[5]Rahardjo H,Ong T H,Rezaur R B,et al.Factors controlling instability of homogeneous soil slopes under rainfall[J].Journal of Geotechnical and Geoenvironmental Engineering,2007,133(12):1532-1543.
[6]Fredlund D G,Rahardjo H.Soil Mechanics for Unsaturated Soils[M].New York:John Wiley&Sons,1993.
[7]檀康,简文星.斜坡降雨入渗迭代计算模型研究[J].安全与环境工程,2015,22(4):168-172.
[8]Srivastava R,Jim Yeh T C.Analytical solutions for one-dimensional,transient infiltration toward the water table in homogeneous and layered soils[J].Water Resources Research,1991,27(5):753-762.
[9]Richards L A.Capillary conduction of liquids in porous mediums[J].Journal of Applied Physics,1931,1(5):318-333.
[10]Green W H,Ampt G A.Studies on soil physics,Part 1.Flow of air and water through soil[J].Journal of Agricultural Science,1911,1(4):1-24.
[11]简文星,许强,童龙云.三峡库区黄土坡滑坡降雨入渗模型研究[J].岩土力学,2013,34(12):3527-3533.
[12]李秀珍,何思明.基于Mein-Larson入渗模型的浅层降雨滑坡稳定性研究[J].灾害学,2015,30(2):16-20.
[13]李宁,许建聪,钦亚洲.降雨诱发浅层滑坡稳定性的计算模型研究[J].岩土力学,2012,33(5):1485-1490.
[14]Godt J W,Sener-Kaya B,Lu N,et al.Stability of infinite slopes under transient partially saturated seepage conditions[J].Water Resources Research,2012,48(5):W05505.
[15]van Genuchten M T.Closed-form equation for predicting the hydraulic conductivity of unsaturated soils[J].Soil Science Society of America Journal,1980,44(5):892-898.
[16]陈洪松,邵明安,王克林.土壤初始含水率对坡面降雨入渗及土壤水分再分布的影响[J].农业工程学报,2006,22(1):44-47.
[17]王云强,张兴昌,从伟,等.黄土区不同土地利用方式坡面土壤含水率的空间变异性研究[J].农业工程学报,2006,22(12):65-71.
[2]戚国庆.降雨诱发滑坡机理及其评价方法研究——非饱和土力学理论在降雨型滑坡研究中的应用[D].成都:成都理工大学,2004.
[3]Polemio M,Petrucci O.Rainfall as a landslide triggering factor:An overview of recent international research[M]//Bromhead E,Dixon N,Ibsen M L.Landslides in Research,Theory and Practice.London:Thomas Telford Ltd.,2000:1219-1226.
[4]Tsai T,Chiang S.Modeling of layered infinite slope failure triggered by rainfall[J].Environmental Earth Sciences,2013,68(5):1429-1434.
[5]Rahardjo H,Ong T H,Rezaur R B,et al.Factors controlling instability of homogeneous soil slopes under rainfall[J].Journal of Geotechnical and Geoenvironmental Engineering,2007,133(12):1532-1543.
[6]Fredlund D G,Rahardjo H.Soil Mechanics for Unsaturated Soils[M].New York:John Wiley&Sons,1993.
[7]檀康,简文星.斜坡降雨入渗迭代计算模型研究[J].安全与环境工程,2015,22(4):168-172.
[8]Srivastava R,Jim Yeh T C.Analytical solutions for one-dimensional,transient infiltration toward the water table in homogeneous and layered soils[J].Water Resources Research,1991,27(5):753-762.
[9]Richards L A.Capillary conduction of liquids in porous mediums[J].Journal of Applied Physics,1931,1(5):318-333.
[10]Green W H,Ampt G A.Studies on soil physics,Part 1.Flow of air and water through soil[J].Journal of Agricultural Science,1911,1(4):1-24.
[11]简文星,许强,童龙云.三峡库区黄土坡滑坡降雨入渗模型研究[J].岩土力学,2013,34(12):3527-3533.
[12]李秀珍,何思明.基于Mein-Larson入渗模型的浅层降雨滑坡稳定性研究[J].灾害学,2015,30(2):16-20.
[13]李宁,许建聪,钦亚洲.降雨诱发浅层滑坡稳定性的计算模型研究[J].岩土力学,2012,33(5):1485-1490.
[14]Godt J W,Sener-Kaya B,Lu N,et al.Stability of infinite slopes under transient partially saturated seepage conditions[J].Water Resources Research,2012,48(5):W05505.
[15]van Genuchten M T.Closed-form equation for predicting the hydraulic conductivity of unsaturated soils[J].Soil Science Society of America Journal,1980,44(5):892-898.
[16]陈洪松,邵明安,王克林.土壤初始含水率对坡面降雨入渗及土壤水分再分布的影响[J].农业工程学报,2006,22(1):44-47.
[17]王云强,张兴昌,从伟,等.黄土区不同土地利用方式坡面土壤含水率的空间变异性研究[J].农业工程学报,2006,22(12):65-71.