盾构周围土压力的试验研究与数值模拟

建立大型盾构模拟试验平台和直径为φ1．8m的盾构机模型，在软土、砂土及砂砾土层中进行盾构模型的掘进试验，在试验中分别采用刀盘开口率为30％和70％的盾构模型进行模拟掘进。模型盾构掘进过程中，监测系统实时采集推力、土舱压力和刀盘扭矩等盾构推进的各种工作参数，重点对模型盾构周围土压力变化及刀盘开口率对土舱内外土压力的影响进行研究。另外，还研究2种不同刀盘开口率对于盾构的推力和刀盘扭矩的影响，并建立模拟盾构掘进的有限差分模型。该模型考虑刀盘开口率的影响，获得盾构周围土体中土压力的动态变化曲线，并将土压力的实测值和计算值进行比较。

EXPERIMENTAL STUDY AND NUMERICAL SIMULATION OF EARTH PRESSURE AROUND SHIELD MACHINE

A large-scale shield experimental platform and a shield model with diameter of 1.8m are considered to simulate the earth pressure around shield machine. Excavation experiments of shield model are conducted in clay, sand and gravel soils. Two different open ratios of 30% and 70% of cutter head, respectively, are applied to the model experiment. The working parameters including thrust force, torque of cutter head and earth pressure of soil cabin are collected during the processes of excavation. Special attentions are focused on the change of earth pressure and effects of open ratio on cutter head with different earth pressures inside and outside of soil cabin. A finite difference model is constructed for the numerical analysis of excavation process, in which the effect of open ratio of cutter head is considered carefully. This numerical model gives the dynamic change of earth pressure in the soil around the shield model; and the calculated values are compared with those monitored in the model experiment.