Compared with the traditional pipe curtain method, the pipe-roof pre-construction method has the characteristics of small jacking pipe spacing and large jacking pipe diameter. At present, there are few applications for close-packed large-diameter pipe jacking. The theoretical studies on the construction sequence of close-packed pipe jacking and the surface settlement law of pipe jacking construction are insufficient. The deformation trend of soil in close-packed pipe jacking construction is quite different from that of single pipe jacking. The traditional Peck formula used to predict the surface settlement is difficult to apply. In order to figure out the construction sequence and deformation law of close-packed pipe jacking construction, a large-scale model test was conducted to study the three typical pipe jacking construction schemes. The interactions between close-packed large-diameter jacking pipes and the characteristics of ground deformation during pipe jacking construction were studied. Based on the test results, in the test scheme considering the pipe soil arching effect, the maximum surface settlement at the central axis of the pipe-roof was only 6.09 mm, which was smaller than the other two sets of schemes. There was not only mutual supports between the densely packed pipes, but also the pipe soil arching effects formed by the pipe joint and the surrounding soil providing a protection for the construction of the lower pipe. The best order of construction was first to construct the upper pipe and then to construct the pipe-roof on both sides and the lower row pipes. The ground surface settlement caused by close-packed pipe jacking construction was predicted by the improved Peck formula, which considered the supporting effect of soil arching between the adjacent pipes, and modified the specific methods of parameter selections. The prediction results of the improved Peck formula were in good agreements with the lateral surface settlement curves obtained by the model tests.
