Prediction of lateral displacement of soil behind the reaction wall caused by pipe jacking operation

摘要

The lateral displacement of the soil behind the reaction wall of an open caisson can affect the efficiency and safety of jacking operation and control. This paper focuses on the deformation induced within the soil mass behind the reaction wall used to support the jack. A numerical approach for shakedown analysis is first proposed utilizing the energy dissipation principle and its effectiveness is verified by one classic computational example. Combining a project involving parallel pipe jacking under the Guan River in Jiangsu, China, specific procedures for displacement prediction with the soil behind the reaction wall based on shakedown analysis are then given. After the reasonableness and necessity of proposed technique is justified by comparison with commonly used method, the dependence of the soil displacement on three important parameters is investigated: the thickness of the reaction wall, elastic modulus of the soil and the position changes of the reactive force. The proposed technique is a new way of predicting displacement with reasonable accuracy for the control of deformation in the soil behind the reaction wall, and the predicted results are valuable references for ensuring construction quality.