Experimental analysis on construction mechanical properties of parallel rectangular pipe jacking based on similar model test

Abstract

According to a parallel rectangular pipe jacking project, a model test research was carried out based on the similarity theory. And the vertical deformation of the surface, earth pressure and pipe strain are discussed in the process of parallel rectangular pipe jacking construction, to analyze the interaction of parallel rectangular pipe jacking construction and the soil layer disturbance effect. The research shows that: 1) the surface settlement value increases gradually when the first pipe is jacked, and the settlement value tends to be stable, but the final settlement value of the first pipe decreases slightly when the second pipe is jacked, and the center of the surface settlement trough shifts from the first pipe to the second pipe. The settlement value at the second pipe is slightly less than that of the first pipe, so the jacking sequence of the parallel pipe should be reasonably selected during construction. 2) With the jacking of pipe, the earth pressure value above the pipe jacking increases first and then decreases. The pipe jacking can reduce the vertical soil pressure under the pipe jacking to a certain extent. In the process of pipe jacking, the excavation amount of soil in the pipe should be set reasonably to control the earth pressure on pipe jacking. 3) In the process of pipe jacking construction, the maximum strain of pipe appears at different positions, which indicates that uneven jacking force will lead to local stress concentration of pipe. Effective measures should be taken to control the jacking attitude of pipe and real-time monitoring should be strengthened. Relevant research results can provide a reference for rectangular pipe jacking design and construction.