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直剪试验具有方便、经济的优点,被广泛应用,提高直剪试验数据的可靠性具有重要意义。在总结前人研究成果的基础上,将直剪试验结果数据的修正分为2类:单点面积修正方法和多点面积修正方法。通过简化受剪切土体受力物理模型,提出基于面积修正和正应力修正的单点面积应力修正方法。结果表明:该方法是有效、可靠的,修正后的强度指标要大于其他2种方法,并且对3种方法的实际运用进行简单探讨。在推导过程中,提出面积修正系数和正应力修正系数。修正系数结果表明:随着剪切位移的增加,有效剪切面上的剪应力大于实测值;有效剪切面积上的正应力小于施加的竖向应力,并且随着剪切位移的增加而逐渐减小;非有效剪切面上的正应力呈逐渐增大趋势。由于直剪试验本身的缺陷,使得其修正后的强度参数与三轴试验结果存在一定差别。提出的单点面积应力修正方法提高了利用直剪试验获取土体抗剪强度参数的可靠性和准确性。
Direct shear test has the advantages of convenience and economy, and is widely used to improve the reliability of direct shear test data is of great significance. On the basis of summarizing the previous research results, the data of direct shear test are divided into two categories: single point area correction method and multi - point area correction method. By simplifying the physical model of the soil under shear stress, a single point area stress correction method based on area correction and normal stress correction is proposed. The results show that the method is effective and reliable, and the revised strength index is greater than the other two methods, and the practical application of the three methods is briefly discussed. In the process of derivation, proposed area correction coefficient and normal stress correction coefficient. The results show that the shear stress on the effective shear surface is larger than the measured value as the shear displacement increases, and the normal stress on the effective shear area is smaller than the applied vertical stress and gradually increases with the shear displacement Decreases; normal stress on the non-effective shear surface is gradually increasing. Due to the defect of the direct shear test itself, the corrected strength parameters are different from the triaxial test results. The proposed single-point area stress correction method improves the reliability and accuracy of obtaining the shear strength parameters of soil using the direct shear test.