Based on the current research studies and needs in engineering , presented and discussed the following four fundamental problems of unsaturated seepage were : numerical modeling theories , modeling of rainfall infiltration , initial water content and hydraulic conductivity and its effect on the numerical simulation 摘要立足于非饱和渗流问题的研究现状和应用需求，对4个常见的非饱和渗流基本问题进行了论述：非饱和渗流及其数值模拟理论；非饱和降雨入渗及其模拟中的问题；初始水分量及其考虑；土的非饱和渗透特性以及对渗流计算结果的影响。
In this dissertation , rainfall infiltration , runoff , and soil water redistribution on a hillslope were studied by simulated rainfall experiments , and soil water cycling was investigated by site observation and soil sampling methods . moreover , the reasons for the desiccation of deep soil layer were analyzed , and its assessment indexes and standards were presented . the main results are as follows : ( 1 ) rainfall infiltration into a planar hillslope with a homogeneous isotropic soil could be simply regarded as one - dimensional infiltration process , if soil erosion was prevented 针对当前该区植被恢复重建中存在的科学问题，以植被建设的关键性限制因素?土壤水分为出发点，通过室内外模拟降雨试验，研究了坡地降雨入渗、产流及土壤水分再分布规律，同时采用定位观测和采样分析相结合的方法，分析了坡地土壤水分的循环与转化特征，并初步建立了深层土壤干燥化程度的评价标准，取得的主要结论如下： ( 1 )在防止土壤侵蚀的条件下，均质坡地的降雨入渗过程可以简化为一维。
( 2 ) the method of finite element discrete and optimal parameter back analysis is adopted . ( 3 ) concentrated on the question of high external water pressure of the deep - lying tunnel , the basic theory and method calculating external water pressure are systematically studied . ( 4 ) based on jinping cascade 2 hydropower station , numerical simulation rain infiltration of seepage field under different drainage pattern and grouting pattern are studied , also , the high external water pressure is analyzed and studied and some seepage control measures are put forward ( 2 )采用有限元离散?优化法进行参数的反演分析； ( 3 )针对深埋隧洞的高外水压力问题，进一步分析和研究了衬砌水荷载及外水压力的作用机理和计算方法； ( 4 )以锦屏二级水电站深埋长引水隧洞作为本文的主要研究对象，采用考虑降雨入渗渗流场分析的方法对排水方案和灌浆封堵方案不同情况下的渗流场的水头分布进行了数值模拟，并对其外水压力进行了分析和研究，提出了渗流控制的具体措施。
The field of water distribution is obtained by finite difference method , then it is transformed into weight field and strength field or the field of suction distribution . the safety factor of slope during the infiltration time is calculated by slice method according to the actual weigh field and strength field 在有限差分法求得土坡水分分布的基础上，提出了用条分法计算土坡在降雨入渗各个时刻安全系数的思路：把水分分布场转化为边坡的基质吸力分布场(强度场)和重量场，用边坡的实际重量场和强度场来进行安全系数的计算。
In the light of high density fractured rock mass , which can be equivalent to continuum , a mathematical model for the analysis on infiltration under different rainfall degrees is established arid a relevant finite element program is worked out with the analysis method of rainfall infiltration used for reference 本文针对裂隙程度比较大的岩体，把边坡岩体等效成连续介质，借鉴降雨入渗的分析方法，建立了不同降雨强度下的入渗分析数学模型并编制了相应的有限元计算程序。
On the basis of the theory about water potential in soils , a partial differential equation of water movement in unsaturated soils is derived , which chose volumetric water content as the control variable . the numerical solution of the equation using finite difference method is discussed in this paper , and the modality to calculate water movement in slope considering rain infiltration 基于非饱和土的土水势理论，本文推导了以体积含水率为因变量的二维非饱和土的水分运动方程，并给出了用有限差分法来求解此偏微分方程的方法，得到了考虑降雨入渗影响的土坡水分运动的计算程式。
" two chain " model for deformation and stability prediction of expansive soil slope is the framework for this research , in which it is considered that the reduction of strength of expansive soils during infiltration is mainly resulted on two aspects : 1 ) soils characteristics variation and 2 ) suction reduction while water content increasing 本文所进行的研究架构在膨胀土边坡变形与稳定预报的“双链”思想的基础上，认为降雨入渗过程中膨胀土边坡土体的强度折减主要来源于两个方面：一是降雨入渗时边坡土体中土的性状的变化；二是降雨入渗过程中由于土体含水量的增加变化导致边坡吸力降低。
Focused on the former in this paper , the fissures of expansive soils regarded as most important characteristics are analyzed through laboratory test , field observation and numerical simulation . scheduled experimental researches are carried out on quantificational description of fissures , healing of fissures during infiltration , seepage characteristics of fissures network and strength characteristics of fissured soil . based on tests results , numerical models for fissures network seepage and unsaturated fissured expansive soil consolidation are developed and applied to a finite element method analysis of an expansive soil slope during infiltration under different fissures states 本文着重研究前者，将膨胀土的裂隙性作为反映土体性状的主要方面，通过室内试验、现场观测以及数值模拟分析方法，对裂隙的观测手段与定量化描述、浸水愈合特征、裂隙网络渗流特性、裂隙土体强度特性等方面进行了全面系统的试验研究，在此基础上建立膨胀土边坡裂隙网络入渗的数学模型和非饱和裂隙膨胀土固结的数学模型，并应用数学模型对降雨入渗条件下不同裂隙发育状态时膨胀土边坡中水气运移、强度与变形特征进行了有限元数值分析。
The unsaturated soil water movement formula is adopted for calculated the transient water content within the slope . with equilibrium method the stability of soil - nail bracing structure of unsaturated soil slope is analyzed considering the connection between the shear strength of unsaturated soil and water content . genetic algorithm is introduced for searching the minimum factor of safety of natural slope and soil - nail bracing in unsaturated soil 运用非饱和土水分子运动方程，求解降雨入渗条件下边坡土体的瞬态体积含水量，又考虑到其与非饱和土抗剪强度的关系，利用极限平衡理论推导了非饱和土边坡土钉支护整体稳定性最小安全系数f _ ( s , min )公式。
The 3d saturated - unsaturated fem program is developed by which changes processes of seepage fields with changes of water level in a certain section of nanjing dike have been analyzed . ( 2 ) based on the saturated - unsaturated seepage theory , the mathematic model under the condition of rain infiltration has been deduced . the problem of mathematic model is primarily solved and the rain infiltration boundaries have been successfully handled （ 2 ）以饱和-非饱和渗流理论为基础，推导了考虑降雨入渗的三维饱和-非饱和渗流数学模型，初步解决了降雨入渗的数学建模问题，而且对于降雨入渗边界条件的合理处理也取得了成功，并对某矿区边坡典型的降雨过程和降雨入渗影响进行了客观的模拟。
