STUDY ON EARTH PRESSURES OF MULTI-STEP GEOGRID REINFORCED SOIL RETAINING WALL BY MODEL TEST

An indoor model groove,which is 8.0 m long,3.0 m wide and 4.5 m high,was built to study the mechanical properties of multi-step geogrid reinforced wall. A series of model tests have been performed on the three-step reinforced wall with each step 1.5 m in height with two types of geogrid reinforcements in the groove. The earth pressures near the wall-plate,rear reinforced body and horizontal profile,the compression stress of the bottom,etc. are measured. It is found that the test data of the earth pressure in different points are inconsistent with the values calculated by the traditional earth pressure theory;and the pressure is closely associated with the mechanical behaviors and the height of the wall. At the same time,the displacement of the base is greatly impacted on the mechanical behaviors of the reinforced body whose pressure will be redistributed,i.e. when the displacement of base is large,the distribution of the pressure in ground is V-shaped;otherwise according to slash distribution. And it is shown that the earth pressure behind the panel is distributed with greater value in the middle and less ones at the bottom and the top. So are the earth pressures in the back of reinforced body,but the amplitude of prominent is smaller. It is also shown the mechanical behaviors in the reinforced body will be changed as the aperture of grid.