软土地层土压平衡盾构法施工的模型试验研究

Experimental study on EPB shield tunnel construction in soft ground

我国沿海地区以及许多内陆城市的地下广泛分布着很深的软黏土沉积层,目前该区域的许多城市都已兴建或正在筹建地铁。为确保在这种软弱地层中能采取与之相适应的盾构工法、减少对周围环境的影响以及降低工程造价,以上海地铁M8线某区间隧道工程为研究背景,采用室内模型试验的方法,进行了土压平衡盾构针对软土地层的适应性试验研究。为此,首先根据相似理论和模型试验方法建立了土体–盾构机器之间的相似系统;随后,针对上海地区特定的软土地层,进行了人工模型土壤的配制和模型试验方法的设计,并利用直径400 mm的模型盾构机模拟直径6340 mm的原型盾构机;最后,进行盾构不同工作参数组合的掘削试验,并记录下试验过程中机器工作参数及土体内应力和变形变化的有关试验结果,通过对试验数据的整理与分析,得出了软土地层中土压平衡盾构法施工的一些有用的规律。

The very deep sedimentary deposits of soft clay are widely distributed over the underground of coastal areas and many interior cities of China. At present, in many cities of such regions, subways have been constructed or have beeing prepared for construction. In order to guarantee the practical use of the shield tunnel method in this kind of weak stratum, and to reduce environmental influence as well as the project construction cost, the interval tunnel of Shanghai subway line M8 was taken as research background, and model tests were carded out to simulate tunneling excavation with EPB shield machine. Therefore, according to the similarity theory and model test method, the similar system between the soil body - shield machine had been established. Afterwards, the artificial soil was configured to formulate the soft soil of Shanghai area and similarity model experiment procedures were designed for tunnefing in such ground. In addition, the prototype shield machine with diameter of 6340 mm was simulated by a microtunneling machine with diameter of 400 mm. Finally, working parameters of various machines were combined for tunneling tests while the test results of machine and soil body were recorded simultaneously. Based on the analysis of test results, some useful conclusions were drawn for EPB shield machine tunneling in soft ground.