Calculation model of peripheral friction resistance of rectangular pipe jacking based on effective soil pressure

In the construction of rectangular pipe jacking, the peripheral friction resistance is an important parameter to study the jacking force and the disturbance of the surrounding soil. In order to predict the peripheral friction resistance of rectangular pipe jacking more accurately, this paper determines the pipe-soil contact state and interfacial friction coefficient under different lubrication and grouting conditions according to the actual construction of pipe jacking, which exists two kinds of working conditions: no mud lubrication at the initial stage of jacking and mud lubrication in the subsequent jacking, and puts forward a method of determining the pipe-soil contact state of the side wall of rectangular pipe jacking based on the theory of Terzaghi soil pressure and the support effect of the mud pressure on the soil around the pipe. The effective soil pressure around the pipe is used to establish the calculation model of peripheral friction resistance of rectangular pipe jacking, and finally it is compared and analysed with the engineering measured data and other formulas.The results show that:the pipe-soil full contact model should be adopted for pipe jacking without mud lubrication, and the contact interface friction coefficient should be adopted as the pipe-soil friction coefficient under the condition of no mud lubrication; under the mud lubrication condition, the general slurry lubrication section is located between the pipe-soil full contact and the pipe-soil partial contact, and the average value of the pipe-soil friction coefficient under the condition of mud lubrication and mud lubrication is used; the subsequent jacking of the synchronous grouting lubrication section, the pipe-soil part of the contact model, through the effective pressure on the side of the pipe section of the 0-value point can determine the specific contact state, the pipe-soil friction coefficient should be used to consider the friction coefficient of the mud lubrication conditions; comparison with the calculated and measured values of the specification reveals that the calculation model in this paper is closer to the measured values in the field, which verifies its accuracy in calculating the peripheral friction resistance of rectangular pipe jacking.