SONG Lu,ZHU Haili,LI Guorong,et al.Comparative Research for Two Experimental Methods to Determine Soil-Root Composite Shear Strength[J].Research of Soil and Water Conservation,2016,23(04):282-287.
两种方法测定根-土复合体抗剪强度试验对比研究
- Title:
- Comparative Research for Two Experimental Methods to Determine Soil-Root Composite Shear Strength
- Keywords:
- In-situ vane shear test; direct shear test; shear strength; vegetation coveraye; water content
- 分类号:
- TU411.7
- 摘要:
- 为了便捷、有效且减少地表破坏面积地原位测定根—土复合体抗剪强度，采用改制后的十字剪切仪在青海大学校内原生植被生长的试验区，分别进行了三种植被覆盖度和三种含水量条件下根—土复合体原位十字剪切试验和室内直接剪切试验。试验结果显示：当土体含水量相同时，室内直剪试验测得的根—土复合体平均粘聚力为20.39~36.49 kPa，原位十字剪切试验测得的根—土复合体抗剪强度为35.92~102.36 kPa；当植被覆盖度相同时，室内直剪试验测得的根—土复合体平均粘聚力为32.46~23.32 kPa，原位十字剪切试验测得的根—土复合体抗剪强度为109.7~68.12 kPa。两种试验结果均表现为：根—土复合体的抗剪强度随植被覆盖度的增大而增大，随含水量的增大而减小。原位十字剪切试验测得的根—土复合体抗剪强度值大于直接剪切试验所测得的剪切强度值，平均增幅达到94.23%。两种试验结果产生差异的主要原因是由于剪切过程中剪切方式、破坏面积、受剪根系的数量及破坏程度不同而造成。其中，原位十字剪切试验是在原位不破坏土体结构和根系分布的基础上，将根—土复合体完全剪破，相对更能准确、直观地反映边坡滑坡过程中的变化规律。
- Abstract:
- In order to determine the shear strength of soil-root composite more effectively and conveniently, and decrease the surface damage area, shear tests were carried out with different vegetation coverage and different water contents by using reformed in-situ vane shear apparatus and direct shear apparatus respectively on the campus of Qinghai University. The experimental results showed that the average cohesion of soil-root composites ranges from 20.39 kPa to 36.49 kPa under same water content by direct shear test, while the average shear strength of soil-root composites ranges from 35.92 kPa to 102.36 kPa through in-situ vane shear test. Then the average cohesion of soil-root composites ranges from 32.46 kPa to 23.32 kPa under same vegetation coverage by direct shear apparatus, while the average shear strength ranges from 109.7 kPa to 68.12 kPa by in-situ vane shear test. The results of two test methods both showed that the shear strength of soil-root composite increased with the increase of vegetation coverage, and decreased with increase of water content. The soil-root composite shear strength of in-situ vane shear test was higher than that of the direct shear test, the average increment reached to 94.23%. The main reasons for making differences between the two methods are due to various shear mode, shear failure area, the number of roots available to shear and damage degree. In situ vane shear test can reflect the change pattern more accurately and visually in the process of landslide because soil-root composites were destroyed completely and the soil structure and root distribution were not destroyed compared with the direct shear test.
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备注/Memo
收稿日期:2015-10-15;改回日期:2015-11-20。
基金项目:国家自然科学基金项目（41302258）；青海大学“123高层次人才培养工程”资助项目；青海大学“地质资源与地质工程创新团队”项目（4056051201）
作者简介:宋路(1991-),男,新疆哈密人,硕士研究生,主要从事地质灾害及其防治研究。E-mail:songlu.2007@163.com
通讯作者:朱海丽(1977-),女,江苏溧阳人,副教授,主要从事植被护坡与滨河生态学研究。E-mail:qdzhuhaili@163.com