单层立体加筋砂土性状的三轴试验研究

Triaxial tests on sand reinforced with one-layer 3D reinforcement

针对加筋土中传统的筋材布置特点,提出了立体加筋土的概念,并设计了采用轴对称布置的单层立体加筋砂土的试验方案,进行了48组镀锌铁皮和橡胶板两种筋材的单层立体加筋砂土的室内三轴试验,探讨了不同立体加筋方式、不同围压作用下应力–应变及强度变化规律。通过试验结果对比,分析了立体加筋砂土同传统水平加筋砂土之间应力–应变关系和强度指标的差异规律,竖向筋高度对立体加筋砂土的强度影响,单侧和双侧布置竖向筋材等两种布筋方式对立体加筋砂土强度的影响,以及不同变形模量的加筋材料对立体加筋土强度的影响。试验结果表明:立体加筋砂土的强度随竖向筋的高度增加而增大;立体加筋不仅能提高砂土的粘聚力,同时也能增加砂土的内摩擦角,尤其是双侧立体加筋砂土;在竖向筋总高度相同时,双侧立体加筋形式比单侧立体加筋能更有效提高砂土的强度。

In conventional reinforced soils, the reinforcements are laid horizontally in the soil. A new concept of soil reinforced with 3 dimensional （3D） reinforcements was proposed in this paper. Triaxial tests were carried out on sand reinforced with one-layer 3D reinforcements （made of galvanized iron sheet and hard plastic sheet）. The behavior of sand reinforced with different 3D reinforcing configurations was studied in terms of stress-strain relationship and shear strength of the soil. Comparison was made between stress-strain relationship and shear strength of the soil reinforced with horizontal reinforcement and with 3D reinforcements. The influences of the height of vertical reinforcements, the Young＇s modulus of reinforcement materials and confining pressures on strength of reinforced sand were discussed. It was shown that 3D reinforcement increased not only the cohesion of the soil but also the angle of internal friction significantly, especially for those reinforced with double-sided 3D reinforcements. Different configurations of 3D reinforcement were discussed and compared. Double-sided vertical reinforcements would result in greater increase in strength than single-sided vertical reinforcements with the same height.