2. Research Question and Basic Assumptions
2.1. Description of Research Questions
Taking the retaining wall as the research object, based on the level of the embankment fill surface after the wall, in the condition of rainfall, infiltration into the wall after the rain water in the soil is different, so the value of the earth pressure on the retaining wall is changing, when arrangement drainage system on the back of wall. As shown in Figure 1(a), where H is the high of wall, h0 is the Initial height of groundwater level, h ∆ is Variation of groundwater level and 0h h h = +∆ is water level line. After the rain into the permeability to fill soil water fails to reach the groundwater or make groundwater level rise, the magnitude of active earth pressure in water line h, above the water line for non-saturated soil, below the water line for saturated soil