加筋钙质砂三轴试验研究

TRIAXIAL TEST STUDY ON REINFORCED CALCAREOUS SAND ZENG Kaifeng

为了探究加筋对钙质砂力学性质及颗粒破碎的影响,使用大型三轴仪对加筋钙质砂和素钙质砂进行了一系列不同加筋层数、加筋材料种类及围压的三轴固结排水试验。研究方法如下:首先通过三轴试验及筛分试验,得到了不同试验条件下钙质砂的主应力差-轴向应变曲线、体应变-轴向应变曲线以及试验后的级配曲线;其次通过试验结果,分析了加筋对钙质砂强度、变形及颗粒破碎的影响;最后通过将钙质砂颗粒破碎与输入能量相关联,得到了钙质砂颗粒破碎的规律。研究结果表明:加筋钙质砂强度明显高于素钙质砂,且加筋效果随加筋层数与筋材2%延伸率割线刚度的增加而增加,但随围压的增加而减少。加筋同时也可以有效抑制钙质砂的剪胀,且加筋层数越多抑制效果越明显。另外,试验结果也表明钙质砂颗粒破碎程度与输入能量之间存在特定的关系,输入能量越大颗粒破碎程度越大,且这种关系与钙质砂加筋与否关系不大。

In order to study the mechanical properties of reinforced calcareous sand,a series of large-scale triaxial consolidation drainage tests were performed on reinforced and unreinforced calcareous sand.The testing variables included confining pressures,types of reinforcing materials and number of reinforcement layers.The study methods were as follows:First,the stress-strain relationships,volume strain-axial strain relationships and grain-size distribution curves after the tests of calcareous sand specimens were obtained by the consolidated-drained triaxial compression tests and sieve analyses.Second,the influences of reinforcement on the strength,deformation and particle breakage of calcareous sand were analyzed by these test results.Finally,the rule of particles breakage was obtained by correlating the particle breakage with the input energy.The study results indicated that the strength of reinforced calcareous sand is much higher than unreinforced calcareous sand,and the reinforcement effect increases with the number of reinforcement layers and the 2%elongation secant stiffness of the reinforcement material,but decreases with confining pressure.The reinforced materials can also effectively inhibit the dilatancy of calcareous sand,and the more the number of reinforcement layers,the more obvious the inhibitory effect.In addition,the relationship between particle breakage and input energy is unique regardless of the reinforcement conditions,and the degree of particle breakage increased with the input energy.