关键词: 隧道开挖, 邻近单桩, 水平反应, Pasternak地基模型, 修正系数

Abstract: Tunnel excavation can reduce the bearing capacity of adjacent pile foundation. How to accurately evaluate the additional pile responses is a problem yet to be solved. A simplified analytical method is developed based on a Pasternak-type two-parameter elastic foundation model and a three polyline-elastic-plastic load transfer model; a two-stage analytical method is used and the effect of lateral soil and heterogeneity characteristics of soil are considered. The validity of the proposed method is verified by the comparative analysis of the results obtained from proposed method, Winkler foundation beam method and boundary element method. Combining with parametric studies of the influencing factors of lateral response of a single pile, correction coefficients are used to correct the maximum lateral response of a single pile in the baseline engineering case, the maximum horizontal displacement and the maximum bending moment of a single pile under the calculation working condition are obtained. The results indicate that in calculating the horizontal displacement, the effect of lateral soil can be ignored, while it should be considered in calculating bending moment. The average ground loss ratio is linearly related to while it presents a nonlinear relationship with tunnel radius R, tunnel axis depth H, distance from the center line of the tunnel x and pile flexibility coefficient .

Key words: tunnel excavation, adjacent single pile, lateral response, Pasternak foundation model, correction factors