Design Of Settlement Control Technology In High Railway Based Under Shield Zone

With the vigorous development of the urban rail transit, more and more cases about the shield undercrossing railway spring up. During the process of construction for the shield undercrossing high-speed railway subgrade, ground settlement or heave will be caused, which will affect the safe operation of railway. Tianjin subway interval shield undercrossing high-speed railway subgrade is chosen as the engineering background. By designing the segments of undercrossing section, the specialized protection design for undercrossing section and by using finite element simulation to forecast the subgrade deformation during the process of shield undercrossing construction, a systematic study of the undercrossing problem is made. This study will ensure safety in the process of construction for the shield undercrossing high-speed railway and provide references for similar engineerings. The major work and conclusions of this dissertation are as follows.Firstly, while considering train load, a structure design is made for the segment of undercrossing section. Different methods are used to calculate and compare internal force of the segments. Moreover, to start with improving the safety of the structure, optimum design for the reinforcement of the segments is made according to different calculation results. This will ensure the safe crossing of the shield and eliminate safety hazards in the later stage.Secondly, many aspects, such as the lectotype of shield machines, the concrete measures in the shield construction, monitoring measurement, secondary deep-hole grouting, as well as the pre-reinforcement measures taken for high-speed railway subgrade are all considered. From these aspects, a systematic specialized design is made for the construction of the shield undercrossing high-speed railway subgrade. Meanwhile, shield tunneling speed, synchronized grouting pressure, the important parameters of grouting capacity and grouting speed are all studied to provide direct reference for construction.Finally,3D finite element simulation is used to forecast the deformation law of subgrade in the process of construction for the shield undercrossing high-speed railway. The calculation results show that taking secondary deep-hole grouting measures has obvious effect on controlling the settlement deformation of subgrade.