增湿条件下膨胀土隧道围岩的稳定性

增湿条件下,膨胀土的强度会降低并产生膨胀力,在两者的共同作用下,膨胀土隧道围岩稳定性会严重降低,有必要研究增湿条件下膨胀土隧道围岩的变形和衬砌受力.采用室内试验和数值模拟的方法对膨胀土隧道围岩稳定性进行研究,对不同含水率的重塑膨胀土进行剪切试验,得出摩擦角、黏聚力与含水率的拟合关系式,运用ABAQUS有限元软件对膨胀土...

Stability of expansive soil tunnel surrounding rock under humidity condition

Under the humidification condition, the strength parameters of the expansive soil will decrease and the expansion force will be generated. Under the combined action of the two, the stability of the surrounding rock of the expansive soil tunnel will be seriously reduced. Therefore, it is necessary to study the deformation and lining stress of the surrounding rock of expansive soil tunnel under the condition of humidification. In this paper, laboratory tests and numerical simulations are used to study the stability of the surrounding rock of the expansive soil tunnel. First, the shear experiment is carried out on the remolded expansive soil with different water contents, and the fitting relationship between friction angle and cohesion and water content is obtained. Then, the ABAQUS finite element software is used to simulate and analyze the excavation process of tunneling in the expansive soil.The temperature field module is used to simulate the humidification and expansion of the surrounding rock of the tunnel, and the stress and displacement of the tunnel before and after swelling were obtained. At the same time, the orthogonal experiment was designed to analyze the influence of various factors on the stability of the shallow buried tunnel in the expansive soil. Results show that after humidification, the stress value at the arch waist of the surrounding rock increases significantly, the stress value at the vault and arch bottom decreases.The longitudinal displacement value at the lining arch bottom increases, and the longitudinal displacement value at the arch top decreases. By designing orthogonal experiments and using range and variance analysis, the most influential factor on stability of the surrounding rock of the expansive soil shallow tunnel is the humidification strength, followed by the over-span ratio, the swelling thickness and the swelling coefficient.