粉土的触变性室内试验研究

发布时间：2018-03-01 14:03

本文关键词： 触变性无侧限抗压强度触变强度恢复程度触变强度比率粉土　出处：《太原理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：社会经济的不断发展促使世界各地建筑物不断地超越原有的建筑模式，地基的可靠性越来越受到人们的重视。工程实际中土体的触变性可能导致地基土体强度降低，造成失稳滑坡、工后沉降等工程灾害。为减少这些工程地质灾害，人们对于土的触变性的研究越来越多，在以往的研究工作中，人们更多关注土体触变机理和触变强度的恢复趋势，而对于土体的触变强度恢复影响因素的研究则比较少。本文在诸多国内外学者针对触变性的研究成果基础上，围绕着粉土触变强度恢复特征进行研究，用无侧限抗压强度试验反映强度变化，采用原状土进行室内振动试验，用以模拟现场土体振动，，研究不同扰动程度下土体的强度恢复程度变化规律；结合土工试验规范中击实试样的制备方法，在控制其他变量不变的情况下，制备不同干密度、击实含水率、粉黏粒含量下的击实试样，研究不同影响因子下土体强度恢复的规律。分析试验结果得到的结论如下： (1)通过不同振动时间控制试样扰动程度，对不同扰动程度的试样进行无侧限抗压强度试验，得出不同扰动程度的无侧限抗压强度试验应力-变形曲线，分析绘出的应力-变形曲线得出，扰动程度越大的土体，其无侧限抗压强度越小。对不同扰动程度的试样进行相同时间的静置，绘制静置之后试样的无侧限抗压强度试验应力-变形曲线，根据静置前后的应力-变形曲线比较得出，经过一段时间的静置之后，不同扰动程度的试样强度均有所恢复。 (2)讨论不同扰动程度下粉土试样触变强度的绝对强度恢复程度和相对强度恢复程度，绘制两种强度恢复程度与扰动程度关系曲线，分析曲线可知，扰动粉土的绝对触变强度恢复程度与扰动程度为正相关关系，而相对触变强度恢复程度与扰动程度为负相关关系。 (3)根据前人成果，引入扰动程度比率和触变强度比率的公式定义，前者可判定试样受扰动影响强弱，后者用来判定试样的触变性影响强弱。可通过两者估算扰动粉土的触变强度的绝对恢复程度和相对恢复程度。 (4)用自制击实仪在保证一定击实功的情况下，制备不同击实含水率、干密度、粉黏粒含量的击实粉土试样，并对试样进行抽真空饱和。对饱和击实试样进行无侧限抗压强度试验，分析不同影响因子下无侧限抗压强度试验应力-变形曲线可知，击实粉土的无侧限抗压强度受击实含水率影响，干侧时强度较高，湿侧时强度较低，且击实粉土的无侧限抗压强度随干密度的增加而升高,随粉黏粒含量的增加而降低。 (5)取静置后的饱和击实粉土试样进行无侧限抗压强度试验，用触变强度比率反映击实粉土触变性影响强弱，将试验所得强度代入触变强度比率公式，绘制触变强度比率-影响因子曲线，分析可得，击实粉土的触变性与干密度、粉黏粒含量成正相关关系，在干侧与击实含水率负相关，湿侧与击实含水率正相关。
[Abstract]:The economic and social development to promote building around the world continue to go beyond the original building foundation model, reliability is more and more attention. The thixotropic soil in engineering practice may lead to reduction in soil strength, instability caused by landslide, settlement after construction engineering disasters. In order to reduce the engineering geological disaster, people study and more for the thixotropy of soil in the research work in the past, people pay more attention to the soil and the thixotropic mechanism thixotropic strength recovery trend, and recovery factors on the thixotropic strength of soil is relatively small.
In this paper, many scholars at home and abroad based on the research achievements of thixotropy, surrounding silt thixotropic strength recovery characteristics were studied, with no changes reflect the strength compressive strength test with undisturbed soil unconfined, indoor vibration test to simulate the in-situ Vibration Research of different disturbance degree of soil under the strength variation degree recovery; preparation method combined with soil test standard compaction sample, after controlling for other variables remain unchanged, the preparation of different dry density, moisture content, clay powder compaction particle content, soil strength recovery factor of different under the influence of law. Analysis of the test results were presented as follows:
(1) through different vibration time control sample disturbance degree of samples with different disturbance degrees of unconfined compressive strength test, stress deformation curves of unconfined compressive strength test of the different degree of disturbance, analysis draw stress deformation curves, soil disturbance degree, the unconfined the compressive strength decreases. The static of the same time on samples with different disturbance degrees, drawing static specimens after the unconfined compressive strength test stress-strain curve, according to the static stress-strain curve before and after comparison, after standing for a long time, the strength of sample recovery different degree of disturbance.
(2) discuss the absolute intensity of silt samples under different disturbance degree of thixotropic strength recovery and relative intensity degree of recovery, the drawing of the two strength and the recovery of the disturbance degree curve, curve analysis, absolute thixotropic strength of silty soil disturbance and the recovery of the disturbance degree of positive correlation, and the relative degree of recovery of thixotropic strength the disturbance degree is negatively correlated.
(3) according to the previous results, the introduction of the definition of the disturbance degree formula ratio and thixotropic strength ratio, the former can determine the specimen affected by disturbance intensity, the influence of thixotropic strength. Can be used to determine the sample estimate the thixotropic strength of silty soil disturbance through both the absolute and relative degree of recovery degree of recovery.
(4) in a certain compaction work with self-made compaction device under the condition of the preparation of different compaction water content, dry density, specimen compacted silt silt and clay content, and the samples were vacuum saturation. The unconfined compressive strength test of saturated compacted samples, analysis of different influence no factor of stress deformation curve of unconfined compressive strength test, compacted silty soil unconfined compressive strength affected by moisture content, high strength of the dry side, the wet side when the strength is low, and the compacted silty soil unconfined compressive strength increased with the increase of the dry density. With the increase of silt and clay content decreased.
(5) the static saturated compacted silt samples of unconfined compressive strength test of compacted silt, thixotropic strength of thixotropic strength ratio, the strength test results into the thixotropic strength ratio formula, draw the thixotropic strength ratio influence factor curve analysis, compacted silts thixotropy and dry density, silt and clay content are positively correlated, in the dry side and the moisture content of the wet side and negative correlation, compaction water content are related.

【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU411

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