Characteristic Experiment Of Deformation Failure Mode And Control Measures Of The Expansive Soil Tunnels

In recent years, with rapid development of China’s transportation structure and infrastructure construction, we have constructed more and more Highway, Railway and Cross-Harbour Tunnels. The expansive soil is a special soil which effects great on roads and other structure constructions. However, due to the large span, difficult rescue, high maintenance costs and bad social impacts, there are still some difficult problems in its design and construction. In this paper, it takes the expansive soil tunnel as the engineering background, focus on the complex problems such as deformations, instabilities and failures, large volume collapse, prevention countermeasures, applies lab tests, numerical simulation and engineering applications to study the deformation failure mode and control measures of the expansive soil tunnels.Firstly, lots of laboratory experiments such as water content, dry density, structural characteristics, void ratio, liquid and plasticity index, shear strength, chemical composition and expansion properties were tested to study the physical, mechanical properties and engineering properties of the expansive soil. The judgment of the expansion capacity was proposed.Secondly, the feature, mode and harm of deformation and mode of the expansive soil tunnel were summarized in order to provide guidance for the subsequent expansion soil tunnel construction. Because of the additional load generated by the sliding slope, which attached to the supporting structure, the steel arch were demaged.Thirdly, due to the deformation and failure process of expansive soil tunnel, supporting strength and geological factors analysis were carried out to pointed out the deformation and failure mechanism of expansive soil tunnel.Fourthly, based on the lab test, the numerical simulation analysis of expansive soil tunnel was carried out. Then the UDEC software was used to simulate the phase. After a comprehensive analysis of the experimental phenomena and numerical simulation results, the construction recommendations are proposed.Finally, the classification of surrounding rock of railway soil tunnels was proposed. Based on the sub-class refinement results, the surrounding rock of deformation and failure was sentenced to less than Vb, which needed to additional supplement support. Considering the feature of the deformation and failure, control measures of expansive soil tunnel was summarized. Closed surface cracks timely; installed the temporary horizontal and inclined support, which were to prevent collapses damaged; carried out surface grouting, which were to reinforcement the earth.