土工织物与吹填土界面作用特性试验研究

筋-土界面强度参数是加筋结构设计和稳定分析的关键技术指标。拉拔试验能较好模拟现场加筋行为而得到广泛的应用。基于拉拔和直剪试验研究了拉拔（剪切）速率对筋-土界面特性和吹填砂强度特性的影响规律及机制，同时探讨了不同填料界面、筋材类型的加筋效果。结果表明：随着拉拔（剪切）速率的增大，吹填砂-筋材-吹填砂界面的抗剪强度下降明显，而软土-筋材-吹填砂界面以及砂本身强度则变化不大。从强度指标来看，拉拔速率增大，筋-砂界面强度的降低主要表现为似黏聚力的降低，筋-软土界面抗剪强度的增加表现为内摩擦角增大，剪切速率对吹填砂则基本无影响。筋-土界面特性受拉拔速率和正应力的共同影响，与筋材类型和填料特性有关。筋-土界面内摩擦角小于填料摩擦角，但在一定正应力下低速剪切时（如<0.53 mm/min）可获得高于填料的抗剪强度。宜根据似黏聚力大小合理选择摩擦参数进行加筋结构的设计与评价。

Experimental studies of interface characteristics between geotextile and hydraulic fill soil

Interface strength parameters are the key technical indices of the design and stability analysis of reinforcement. The pullout test is widely used for its better simulating of the field reinforced behavior. Through pullout test and direct shear test, the research focuses on the law and mechanism of the pullout (shear) rate’s influence on reinforcement interface characteristics and hydraulic fill sand, and the reinforcement effect of different fillers and different geosynthetics are discussed. The results show that: with the increase of pullout (shear) rate, the shear strength of sand-geotextile-sand interface decreases greatly while clay-geotextile-sand and sand-sand interfaces change little. From the perspective of strength index, sand-geotextile shear strength decreases mainly caused by the decrease of cohesive force; clay-geotextile shear strength increases mainly caused by the increase of friction angle; shear rate has little influence on hydraulic fill sand. Friction angle of reinforced soil is less than that of the soil itself. The interface characteristics of reinforcement are influenced by both pullout rate and normal stress level, related with type of geosynthetics and characteristics of soil. The choice of friction parameter for design and evaluation of reinforced structure should accord to the size of cohesive force.