细粒土不均匀分布对粗粒土力学特性的影响

发布时间：2018-03-02 13:18

本文选题：细粒土　切入点：不均匀分布　出处：《岩土工程学报》2017年03期 　论文类型：期刊论文

【摘要】：为了研究冻融循环条件下细粒土的不均匀分布特性对粗粒土力学特性的影响,对不同冻融循环次数、冻结温度、围压条件下的含有不同细粒土分布的粗粒土进行常规的静三轴剪切试验,研究冻融循环后具有不均匀细粒土分布的试样的最大剪胀位置、应力应变关系曲线、起始屈服强度、起始屈服应变、静强度、破坏应变变化规律。研究结果表明,在相同的细颗粒与粗颗粒不均匀分布的条件下,试验后试样的最大剪胀位置随着试样上两层中细粒土含量的增加而沿着试样高度上升,随着冻融循环次数的增加,最大剪胀位置的上升速率是不断增加的。细颗粒与粗颗粒不均匀分布的程度越高,尤其是粗颗粒的富集程度越高,试样的脆性越高,试样的应变软化程度越明显。冻融循环次数的增加,降低了粗、细颗粒较均匀分布的3种试样的应力应变软化程度的差异性,即冻融循环次数的增加可以使粗颗粒和细颗粒的组合结构趋于稳定。在相同的围压条件下,冻融循环次数的增加削弱了因细粒土不均匀分布而导致的起始屈服强度的差异性和静强度的差异性。试样中的粗颗粒和细颗粒分布越不均匀,试样的起始屈服强度和静强度越大。当围压为100 k Pa时,静强度与起始屈服强度的比值随冻融循环次数波动较大,当围压增加到300 k Pa时,比值随冻融循环次数的波动较为平缓。细粒土不均匀分布是起始屈服应变和破坏应变的最显著性影响因素,但是围压对破坏应变的影响程度明显大于围压对起始屈服应变的影响程度。细粒土不均匀分布对破坏应变影响的显著性明显小于它对起始屈服应变影响的显著性。
[Abstract]:In order to study the effect of non-uniform distribution of fine soil on the mechanical properties of coarse grained soil under freeze-thaw cycle, different freezing and thawing cycles and freezing temperatures were studied. Under confining pressure, coarse grained soil with different fine grained soil distribution was tested by conventional static triaxial shear test. The maximum shear heaving position and stress-strain relation curve of samples with uneven fine grained soil distribution after freeze-thaw cycle were studied. The variation of initial yield strength, initial yield strain, static strength and failure strain. The results show that under the same conditions of uneven distribution of fine and coarse particles, After the test, the maximum shear heaving position of the specimen increases with the increase of the content of fine soil in the top two layers of the sample, and increases along with the height of the specimen, and with the increase of the number of freeze-thaw cycles, The higher the degree of uneven distribution of fine particles and coarse particles, especially the higher the enrichment degree of coarse particles, the higher the brittleness of the samples. The more obvious the strain softening degree of the sample is, the lower the difference of stress and strain softening degree of the three samples with coarse and fine particles is decreased with the increase of freeze-thaw cycle times. That is, the combination structure of coarse and fine particles can be stabilized by increasing the number of freeze-thaw cycles. Under the same confining pressure, The increase of freeze-thaw cycles weakens the difference of initial yield strength and static strength caused by uneven distribution of fine grained soil. When the confining pressure is 100 KPA, the ratio of static strength to initial yield strength fluctuates greatly with the number of freeze-thaw cycles, and increases to 300 KPA when confining pressure increases to 300 KPA. The ratio fluctuates slowly with the number of freeze-thaw cycles. The uneven distribution of fine grained soil is the most significant influence factor of initial yield strain and failure strain. However, the influence of confining pressure on failure strain is obviously greater than that of confining pressure on initial yield strain, and the influence of non-uniform distribution of fine grained soil on failure strain is obviously less than that on initial yield strain.
【作者单位】：北京交通大学土木建筑工程学院;
【基金】：国家重点基础研究发展计划(“973”计划)项目(2012CB026104) 中央高校基本科研业务费专项资金项目(2016YJS107) 国家自然科学基金项目(41271072,41371081,51378057)
【分类号】：TU43

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