1. College of Architecture and Civil Engineering, Xi’an University of Science and Technology, Xi’an 710054, China 2. College of Civil Engineering, Tongji University, Shanghai 200092, China 3. Pile-supported Structures Research and Test Center, Xi’an University of Science and Technology, Xi’an 710054, China
The coal gangue pile, geocell and grid were used as vertical and horizontal reinforcements respectively for static load test in order to analyze the bearing capacity of coal gangue pile-geocell composite subgrade. The variation rules of tensile stress of geocell and grid, axial stress of pile and soil pressure between pile top and pile were analyzed. Results show that when the eighth load is applied, the tensile stress on the geocell increases by 67.93% compared with the geogrid, and the stress at the neutral point of the center pile and the side pile of the cell group increases by 78.22% and 30.95% respectively. The corresponding section of the neutral point was located in the middle of the pile about 50 cm from the top of the pile. Compared with the grid group, the pile-soil stress ratio of the cell group under the reinforced cushion was increased by 13.68% in the middle of the subgrade, 12.40%-13.49% in the edge of the subgrade, and 13.19% in the whole. The coal gangue pile-geocell composite structure can effectively transfer the load from the pile body to the base. The geocell reinforced cushion uniformly laterally transmits the load to the reinforced body, weakening the soil arching effect between piles and soil, and the flexible raft effect composed of geocell and cushion is more prominent.
Fig.5Arrangement of strain gauge and earth pressure cell
Fig.6Arrangement of stiffened body measuring point
Fig.7Sketch of loading and measuring
Fig.8Stress of geocell
Fig.9Stress of geogrid
Fig.10Pile stress of cell group
Fig.11Pile stress of grid group
Fig.12Pile-soil stress ratio of first layer
Fig.13Second layer stress ratio
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