关键词: 矩形顶管, 土柱理论, 摩阻力, 顶进参数, 环境影响, 地表沉降

Abstract: Long-distance pipe jacking through complex geological strata faces the challenges of difficult jacking, difficult mud wall formation, and excessive ground disturbance. To address these issues, a case study is conducted on a long-distance rectangular pipe jacking project crossing underneath Beijing-Hangzhou Grand Canal, and the mechanical behavior of long-distance pipe jacking and the influence of pipe jacking on surrounding environment are systematically examined. Based on the friction coefficient of slurry obtained from field test, the peripheral friction resistance of the pipe is calculated using soil column theory, thus obtaining the pipe jacking force at different jacking distances. The varying process of jacking force, speed, and parameters (slurry feeding pressure, grouting pressure, and slurry chamber pressure) in response to long-distance pipe jacking underneath river is analyzed, and the surface settlement pattern under double-line pipe jacking condition is summarized. Some conclusions are drawn as follows: (1) The pipe jacking force calculated by slurry lubrication theory is reduced by approximately 40%, which is closer to actual values. The slurry lubrication theory improves the calculation accuracy by adjusting friction coefficient. (2) When jacking in different strata, the difference in the properties of the strata and the large pipe jacking deflection angle lead to significant change in jacking force. (3) Under high water pressure condition, controlling the grouting pressure according to burial depth and water pressure effectively guarantees stable working face and surrounding soil, minimizes ground disturbance, thus avoiding excessive vertical surface displacement and water gushing disaster.

Key words: rectangular pipe jacking, soil column theory, frictional resistance, jacking parameters, environmental impact, ground settlement