双层立体加筋砂土的强度特性

在提出立体加筋方式的基础上,对水平–竖向复合加筋和竖向加筋两种加筋形式的立体加筋砂土进行大量的三轴试验。结果表明,相对于无筋土及传统的水平加筋砂土而言,立体加筋砂土强度有大幅度提高。对比分析竖向加筋率与立体加筋砂土强度之间的关系,比较不同围压下的强度变化。在试验基础上,分析立体加筋砂土的工作机制,并利用极限平衡理论建立双层立体加筋土的强度模型,最后将竖向加筋砂土的部分试验结果与理论值进行对比,结果表明二者基本吻合。

STRENGTH PROPERTIES OF TWO-LAYER THREE-DIMENSIONAL REINFORCED SAND

For conventional reinforced soils,the reinforcements are often laid horizontally in the soil.A novel concept of three-dimensional reinforced soil is proposed in this paper.In the proposed 3D reinforced soil,besides the conventional horizontal reinforcements,some vertical and three-dimensional reinforcing elements are also placed in the soil.A series of triaxial tests are carried out on reinforced sand with two-layer horizontal-vertical 3D reinforcements and vertical reinforcements respectively.The results of triaxial tests show that the ultimate deviator stress at failure increases greatly for three-dimensional reinforced sand compared with unreinforced sand and horizontally reinforced sand.Furthermore,the internal friction angle of three-dimensional reinforced sand increases significantly;and cohesion exhibits a similar tendency.The behaviors of sands reinforced with different three-dimensional reinforcing configurations and different reinforcing ratios are studied in terms of stress-strain relationship and shear strength of sand.Based on the experimental results,the mechanism of the three-dimensional reinforced soil has been analyzed and the strength model of the two-layer three-dimensional reinforced sand has been proposed by means of the limit equilibrium theory.The results of analytical prediction are compared with those obtained from the triaxial tests.It is shown that the results of the analytical solution are in good agreement with those from triaxial tests.