Unloading model test on open cut tunnels in high filled loess trench
MA Li1，LI Sheng2，WANG Qicai2，GENG Shaobo3，ZHANG Yanjie2，LI Jianxin2
(1. College of Civil Engineering，Lanzhou Institute of Technology，Lanzhou，Gansu 730050，China；
2. College of Civil Engineering，Lanzhou Jiaotong University，Lanzhou，Gansu 730070，China；
3. College of Civil Engineering，North University of China，Taiyuan，Shanxi 030051，China)
Abstract：In order to study the variation of vertical earth pressure and soil settlement of the open cut tunnel in high filled loess trench under different unloading measures，the unloading effect in different schemes were analyzed and compared through the indoor model test. The results show that increasing the angle of the filling slope，setting the low compacted soil on the top of the open cut tunnel，laying the geogrid and improving the compression modulus of filling on both sides of the open cut tunnel reduce the earth pressure on the top of open cut tunnel. The increase of slope angle has the best effect. The vertical earth pressure on the top of the open cut tunnel is reduced 20.6% in comparison with the one without the slope. The soil arch effect of low compacted soil and the effect of geogrid reduce further the vertical earth pressure on the top of the open cut tunnel. The vertical earth pressure is almost uniformly distributed when the height of earth filling is low. The vertical earth pressure decreases at first and then becomes stable as the increase of the filling height. The setting of low compacted soil resultes in a jump of the vertical earth pressure near the interface of virtual and compacted soil.
马 莉1，李 盛2，王起才2，耿少波3，张延杰2，李建新2. 沟槽式高填黄土明洞卸载模型试验研究[J]. 岩石力学与工程学报, 2016, 35(5): 1065-1071.
MA Li1，LI Sheng2，WANG Qicai2，GENG Shaobo3，ZHANG Yanjie2，LI Jianxin2. Unloading model test on open cut tunnels in high filled loess trench. , 2016, 35(5): 1065-1071.
LARSEN N G，HENDRICKSON J G. A practical method for construction rigid conduits under high fills[C]// Proceedings of the 41st Annual Meeting of the Highway Research Board. Washington，D. C.：[s. n.]，1962：273-280.
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