煤矸石桩-土工格室复合路基承载特性

Bearing characteristics of coal gangue pile-geocell composite subgrade

为了研究煤矸石桩-土工格室复合路基的承载性能,以煤矸石桩、土工格室及格栅分别作为竖向、水平向加筋体,开展静载试验,分析土工格室和格栅拉伸应力、桩体轴向应力以及桩顶与桩间土压力的变化规律.研究结果表明:当施加到第8级荷载时,相较于土工格栅,土工格室上的拉应力增大67.93%,格室组中心桩与边桩中性点应力分别增大78.22%、30.95%,中性点对应截面位于桩体中部距桩顶约50 cm处;加筋垫层下方格室组的桩土应力比与格栅组相比,路基中部增大13.68%,路基边缘部分增大12.40%~13.49%,整体增大13.19%.煤矸石桩-土工格室复合结构能够有效地将荷载由桩身传递至基底;土工格室加筋垫层均匀地将荷载横向传递至加筋体,削弱桩土间的土拱效应,土工格室与垫层构成的柔性筏板效应更突显.

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.