土体抗拉强度试验研究方法的综述

Review of Experimental Testing Methods of Soil Tensile Strength

土体抗拉强度比抗压和抗剪强度数值更小,因此时常被忽略,造成理论及试验的落后。文中系统归纳了土体抗拉强度的间接和直接方法,对比分析了现有试验方法的优缺点,结果表明:(1)土体抗拉强度的单轴拉伸方法按照力的加载方向可以分为垂直法和水平法,而垂直法中土样破坏前上半部分的重量会影响试验的准确性;(2)常用的土样固定方式有粘结、锚固、摩擦力和夹持,它们各有优势,但夹持较前三者更便捷和可操作。最后,提出水平单轴拉伸试验的后续仍需优化的问题。如制样脱模中土样的损耗、土样受拉段应力分布差,无法适用于大骨料砾质土、土样固定方式繁琐、土样与平台间的摩擦力难以消除等。

The tensile strength of soil is significantly lower thanits compressive and shear strengths,leading to its frequent neglect in theoretical and experimental research.This paper provides a comprehensive review of both direct and indirect methods for measuring soil tensile strength,comparing and analyzing the advantages and disadvantages of existing testing techniques.Our findings indicate the following:(1) The uniaxial tensile strength of soil can be categorized into vertical and horizontal methods based on the direction of applied force.The vertical method's accuracy is compromised by the weight of the soil sample above the failure plane.(2) Common methods for securing soil samples include bonding,anchoring,friction,and clamping,with clamping proving to be more convenient and practical than the other techniques.We recommend optimizing the horizontal uniaxial tensile test due to several issues,such as soil sample loss during preparation and demolding,uneven stress distribution across the tensile section,inapplicability to large-aggregate gravelly soils,cumbersome sample fixation,and challenges in minimizing friction between the soil sample and the testing platform.