黄土台塬正在引起公众以及工程地质界的重视。这是因为引水灌溉工程、水电工程的扩建虽然提高了农业的基本产值，但也引起了较多的地质灾害，影响深远。本文以黑方台灌区塬边黄土斜坡为研究对象，通过对地质环境、斜坡灾害特征、灌溉水作用等较为全面的系统探索，取得的主要成果包括： （1）提出“塬边距”概念，建立“塬边距”水文地质模型和数学模型，利用GESTUDIO软件，进行非饱和瞬态渗流数值模拟。结果表明：“塬边距”（灌溉边界至塬边距离）是影响塬区及塬边斜坡体内地下水位抬升和渗透流速的关键因素，灌溉10年间，“塬边距”为100m和0m时，最大渗透流速由0.810m/d增加至0.850m/d；塬区地下水位线高程由灌前1642m上升至1660m和1665m，坡体内地下水位线高程由灌前1642m上升至1651.75m和1656.75m；-150kPa孔压线由分布于坡面和坡顶转移至仅分布于斜坡坡面。 （2）基于“塬边距”概念模型，建立“灌溉强度”模型，进行非饱和瞬态渗流数值模拟。结果表明：灌溉10年间，灌溉强度由300×104m3增加至900×104m3时，最大渗透流速由0.810m/d增加至0.852m/d；塬区地下水位线高程由灌前1642m上升至1657.50m和1671.50m，斜坡体内地下水位线高程由灌前1642m上升至1652m和1661m。 （3）基于非饱和抗剪强度的极限平衡法，考虑地下水位线变化与斜坡土体内基质吸力分布状态的关系，并且利用了Morgenstern-Price法，对塬边斜坡地质模型进行了稳定性分析。稳定分析结果是：当灌溉强度一定（500×104m3/a），随“塬边距”的减小，斜坡稳定系数逐渐递减，当“塬边距”小于50m时，斜坡稳定系数均小于1.100，说明斜坡处于欠稳定或不稳定状态，“塬边距”50m是一阀值，称为斜坡稳定安全距离。 （4）提出两套地下排水方案，即“竖井”和“平孔”排水，建立水文地质概念模型及数学模型，验证其排水时效性。对“竖井”方案，灌溉10年间，“塬边距”由100m减小至0m、灌溉强度由300×104m3增加至900×104m3时，塬边斜坡稳定系数皆高于1.150；对“平孔”方案，灌溉10年间，“塬边距”由100m减小至0m、灌溉强度由300×104m3增加至900×104m3时，塬边斜坡稳定系数皆高于1.200。结果表明，两方案均能快速降低坡体内地下水位，减小了孔隙的水压，增大了有效正应力，增强了土体的抗滑力。

The Loess Plateau is the focus of public attention and engineering geological community.This is because the irrigation project, the construction of hydropower projects to promote agricultural production in the Loess Plateau region, but also brought a series of environmental geological problems, far-reaching. This paper takes the Heifangtai tableland edge of loess slope as a research target, according to the exploration of geological environment, slope disaster characteristics, effects of irrigation water, launched a rather comprehensive and systematic exploration,the main achievements include: （1）Put forward the concept of "Yuan bian ju"(the distance between the irrigation border of the plateau edge ), to establish"Yuan bian ju" hydro geological model and mathematical model,used GSTUDIO software, launched numerical simulation of unsaturated transient seepage.The results showed that:the "Yuan bian ju" is the key factor affecting the plateau and plateau uplift of underground water level and seepage velocity of slope. For irrigation during the 10 years,the "Yuan bian ju" decreased from 100m to 0m, the maximum penetration velocity increased from 0.81m/d to 0.85m/d,the underground water level elevation of plateau by 1642m before reperfusion increased to 1660m and 1665m;the underground water level elevation of the slope by 1642m before reperfusion increased to 1651.75m and 1656.75m,the pore water pressure line of -150kPa transferred from the slope surface and the top of the slope to slope surface. （2）Based on the "Yuan bian ju" conceptual model, to establish the "irrigation intensity" model,launched numerical simulation of unsaturated transient seepage.The results showed that:for irrigation during the 10 years,when the irrigation intensity increased from300×104m3to900×104m3,the maximum penetration velocity increased from 0.81m/d to 0.852m/d,the underground water level elevation of plateau by 1642m before reperfusion increased to 1657.5m and 1671.5m;the underground water level elevation of the slope by 1642m before reperfusion increased to 1652m and 1661m. （3）Based on the shear strength of unsaturated limit equilibrium method,considering the relationship between underground water level change and slope soil within the matrix suction,using the method of Morgenstern-Price,instantiating the stability evaluation of plateau slope.The results showed that:when the irrigation intensity is constant（500×104m3/a）, the slope stability coefficient decreased with the decreasing of "Yuan bian ju",when the "Yuan bian ju"is less than 50m, the stability coefficient of slope is smaller than 1.1,this shows that the slope in the less stable or unstable state."Yuan bian ju"50m is a threshold, called the stability and safety of slope distance. （4）Designed two sets of underground drainage scheme, namely "shaft" and "horizontal hole".To establish hydro geological conceptual model and mathematical model, verified the drainage effectiveness.For "shaft" scheme,for irrigation during the 10 years,the "Yuan bian ju" decreased from 100m to 0m,the irrigation intensity increased from 300×104m3 to900×104m3,the coefficient of slope was greater than 1.15;for "horizontal hole"scheme,for irrigation during the 10 years,the "Yuan bian ju"decreased from 100m to 0m,the irrigation intensity increased from 300×104m3to900×104m3,the coefficient of slope was greater than1.2.The results showed that the two scheme could quickly reduce the underground water level of slope, greatly reduce the pore water pressure,increasing the effective normal stress,improving the sliding resistance force of the soil.