陕西延安Q_2原状与重塑黄土抗拉强度对比试验研究

Comparative experimental study on tensile strength of undisturbed and remolded Q_2 loess from Yan'an Shanxi,China

对陕西延安新宝塔山隧道Q2原状黄土和重塑黄土进行了不同加载速率的无侧限抗压与贯入抗拉试验,研究了加载速率对黄土抗压和抗拉强度的影响,同时研究了加载柱直径对重塑黄土抗拉强度的影响。结果表明:加载速率对抗压强度和抗拉强度的影响较大,抗压强度与抗拉强度均随加载速率的增大而增大,加载速率为1.0mm/min时其抗压强度和抗拉强度值均比较稳定。原状黄土的压拉强度比在10.24~13.68之间,重塑黄土的压拉强度比在18.3~19.9之间。Q2黄土的灵敏度随加载速率的变化范围为5.78~7.14,为灵敏性黏性土,具有较强的结构性。Q2原状黄土与重塑黄土抗拉强度比值在8.40~10.88之间。黄土抗拉强度与加载柱直径之间呈线性增长关系。研究可供土体抗拉强度试验参考,也可为土体抗拉强度试验方法的规范化和标准化提供基础数据。

The unconfined compressive and unconfined penetration tensile tests were conducted with different loading rates for undisturbed and remolded Q2 loess from Baotashan Tunnel in Yan'an,Shanxi. The impact of loading rates on the unconfined compressive strength and tensile strength and the impact of diameters of loading cylinder on tensile strength were studied. It was indicated that the loading rates have a great impact on the compressive strength and tensile strength for undisturbed and remolded loess,where the compressive strength and tensile strength all increased with the increasing of loading rates. The compressive strength and tensile strength were at a steady state when loading rates was1. 0mm / min. The ratios of compressive strength to tensile for the undisturbed Q2 loess varied from 10. 24 to 13. 68,and those for the remolded Q2 loess varied from 18. 3 to 19. 9. The sensitivity of the Q2 loess under different loading rates varied at 5. 78 to 7. 14,so it can be termed as sensitivity clayey soil and has strong structural strength. The ratios of tensile strength of undisturbed Q2 loess to that of remolded Q2 loess varied from 8. 40 to 10. 88. The remolded loess tensile strength increased linearly with the diameters of loading cylinders. The test method and results can be used for valuable reference for the testing of tensile strength of soil,and provide fundamental data and theoretical evidence for standardization of test method.