Abstract: Based on the analytical stiffness matrix solution for layered soil, the calculated method for additional loads induced by the pipe bulkhead additional pressure, and the propulsion friction force between the shield and surrounding soil, and the interaction forces, is derived by means of five-node Gauss-Legendre integral arithmetic. The distribution rule for vertical additional loads induced by pipe jacking construction is analyzed. Furthermore, the influences of equivalent uniform characteristics, soil mechanical parameters, spacing distance for calculation point, and pipe buried depth on additional loads are discussed. The research results show that the peak compressive stress is rapidly achieved ahead by the shield opening according to the additional loads due to the friction force. The value and influence scope of propulsion effects due to the friction force is more obvious than that due to bulkhead additional pressure. The friction force is the main influence factor of additional loads induced by pipe jacking. In addition, the change of layered soil parameters will lead to a certain extent impact on additional loads. The equivalent uniform characteristics, spacing distance for calculation point, and pipe buried depth have distinct influences on the magnitude and distribution of additional loads. The results may provide certain basis to draw up correctly protective measurements of geotechnical environments influenced by pipe jacking construction. The research results can also provide theoretical references to the other projects such as metro tunnel engineering.

Key words: pipe jacking, layered soil, vertical additional load, influence factor, analytical stiffness matrix solution