The Model Test Research On Pile-supported Relieving Retaining Wall

The pile-supported relieving retaining wall is a new type of retaining wall, which has been adopted successfully several times in Shenzhen areas. The horizontal earth pressure is reduced and the internal force distribution of the column and pile is optimized by the reliving slab rigidly connected with the column. This type of structure is featured with reliability, safety, and applicability in some cases. However, its design and calculation method hasn't been set up precisely, and a series of fundamental theory, including earth pressure distribution, and interaction mechanism of the retaining wall-soil fill need more research and development. It's meaningful to promote the usage of this type of retaining wall according to the model test conclusion.The test designed and constructed the model-box and the model-structure for the model test of the pile-supported relieving retaining wall, then carried out corresponding model tests of relieving slab. Earth pressure cells were installed on the back of retaining wall and surfaces of piles, as well as the top and bottom surfaces of the relieving slab, which were used to measure the earth pressure value and distribution. The dial indicators were installed along the columns to measure the deformation of the retaining wall. The way of loading is gasbag pressurization which was used to imitate the functions of actual loading to the retaining wall. The test aims is to study the pressure distribution and the deformation mechanism of the retaining wall as the width and the embedding depth of relieving slab varied. The results of the test indicate that the ratio of the embedding depth to the width plays a crucial role in the pressure distribution and the deformation mechanism of the retaining wall. The actual pressure distribution of the soil around the piles approaches the result by the"m"method.The paper presents the law of active horizontal pressure distribution and the calculation method of the pile-supported relieving retaining wall based on the actual test results. The pressure distribution of up wall is between the Rankine active pressure and the standstill pressure; meanwhile, the pressure distribution of down wall is in accordance with Rankine active pressure. Combined with the theory analysis with the pressure value as the index, the optimal ratio scope of the embedding depth to the width is 1 to 1.9; the ratio of the up to down wall is 1.0.