盾构施工影响下砂土地层变形规律模型试验研究

为了研究盾构施工影响下隧道埋深、地层损失率、颗粒级配对砂土地层变形规律的影响,设计由试验模型箱、隧道开挖模拟装置以及非接触试验监测系统组成的模型试验系统,利用该试验系统对10种试验工况进行研究.试验模型箱是由钢化玻璃板、底部钢板以及刚框架组合而成的开口箱体,砂性地层采用完全烘干的砂土来制作,盾构开挖过程通过一种能够精确...

Model Experimental Study on Stratum Deformation of Shield Tunnelling in Sand

To study the influence of cover depth, ground loss ratio, and particle gradation on the stratum deformation of shield tunnelling in sand, a model test system was designed, which consisted of a test model box, tunnel excavation simulation, and non-contact measurement system. This test system was used to research 10 experimental conditions. The test model box was an open box, which was made up of a tempered glass, bottom steel plate, and rigid frame while the sandy layer was made of completely dried sand. The shield excavation process was simulated by a small cylindrical transmission, which could precisely control the ground loss ratio. The formation changes were monitored by a video measurement system during the test process. First, the results show that with an increase in cover depth, the soil disturbance range gradually expands to both sides, and the maximum settlement value of the ground surface gradually decreases. Settlement through the width increases significantly and the core settlement area above the tunnel decreases gradually as it approaches the depth of the arch. Secondly, there is an obvious linear relationship between stratum deformation and ground loss ratio. Thirdly, the larger the sand particle size, the smaller the maximum settlement value of the ground surface, and the larger the settlement through width. When the ratio of maximum particle size to minimum particle size is constant, the maximum settlement decreases with the increase of particle size of sand. When the maximum particle size is constant, maximum settlement increases with the increase of particle size range in the range of stratum settlement. Finally, the results show the surface settlement curves under different cover depths, ground loss ratios, and particle gradations have similar Gaussian distribution, which drops sharply toward the middle line of the tunnel and gradually becomes slower toward the distance, similar to the law of stratum deformation.