为研究“管幕冻结法”这一新型工法中 “钢管-冻土”复合结构接触面剪切强度的影响因素及规律，基于港珠澳大桥拱北隧道工程，通过变角剪切试验方法设计不同剪切角度的试验，对温度和粗糙度2个维度进行探究，试验结果拟合出-5、-10、-15、-20、-25 ℃ 5种温度条件以及R=0.0、0.3、0.5 mm 3种粗糙度条件下的剪切面剪切强度包络线。试验结果表明： 温度对钢管-冻土接触面内摩擦角影响不大； 对接触面黏聚力，在-15 ℃之前，黏聚力近似呈线性增长，在-15 ℃达到峰值，在-20 ℃达到波谷，继而随温度的降低而增加。钢管-冻土接触面粗糙度的增加对结构面剪切强度的提高具有正向促进作用，但粗糙度过大会对接触面处的冻土体结构（如冰颗粒和土颗粒间隙等）造成一定的内部损伤，导致剪切强度下降。试验给出最优剪切强度下的温度及粗糙度取值区间。

The study on factors influencing the shear strength of the interface of steel pipefrozen soil composite structure in freezesealing pipe roof method(FSPR) is of great significance. In this paper, based on the construction method applied to the Gongbei Tunnel project of Hong KongZhuhaiMacao Bridge, a test of different shear angles using variable angle shear test method is conducted from the aspects of temperature and roughness; the shear strength envelopes of the shear surface under 5 temperature conditions of -10 ℃,-10 ℃, -15 ℃, -20 ℃ and -25 ℃ and 3 roughness conditions of 0 mm, 0.3 mm and 0.5 mm are fitted. The test results show that: (1) The temperature affects the friction angle of the steel pipefrozen soil composite structure little. (2) The cohesive force increase linearly below -15 ℃ and peaking at -15 ℃, then reaches a minimum at -20 ℃, and the cohesive force is negatively correlated with temperature below -20 ℃. (3) The increase of the roughness of steel pipefrozen soil interface has a positive effect on the shear strength, however, the influence is not linear. Excessive roughness will cause internal structure damage of the frozen soil at the interface (such as ice particles, soil particle gap, etc.), resulting in the decrease of the shear strength. The results provide the proper range of temperature and roughness under the optimum shear strength.