基于温度场的南宁盆地泥岩试验研究

发布时间：2018-05-25 20:48

本文选题：泥岩 + 升温　；参考：《广西大学》2016年硕士论文

【摘要】：南宁地区广泛分布着古近系的泥岩,在建筑施工中常常有由于泥岩的劣化导致边坡滑动、基坑垮塌以及地基软化等问题,造成较大的经济损失,也常造成一些安全事故。以往的研究当中更多的注重水-岩相互作用的结果,而忽略了温度对泥质岩这类软质岩影响的过程,因为温度对泥质岩损伤的程度,直接关系到水-岩相互作用的效应。鉴于对上述因素的考量,本文运用现场取回的土样制成重塑样,运用模型试验和小样试验对温度对于泥岩的影响进行综合分析与研究。首先泥岩在温度场影响下泥岩内部温度场和含水率的分布以及变化趋势。接下来的小样试验着重研究在不同温度作用条件下泥岩的力学性质与水理性质的变化,并将小样试验结果反馈在模型试验上,综合分析得出由于温度对泥岩在不同深度的影响以及变化规律。通过模型试验结合小样试验最终得出以下结论： (1)泥岩的持温能力很大程度取决于泥岩的含水率,表层泥岩受温度影响大,水分向外迁移快从而造成含水率降低,比热容也随之降低,泥岩的损伤更易发生；而深层的泥岩受温度影响弱,水分向外迁移缓慢从而含水率变化不大,比热容相对恒定,泥岩的损伤不易发生。(2)温度越高且越干燥的泥岩(表层)试样遇水崩解速度越快,而温度对于含水率较高的泥岩(深层)试样的崩解速度几乎没有影响(3)温度对于泥岩的作用主要是以水为桥梁对泥岩的含水率进行影响,从而影响泥岩的力学和热学性能以及水理性质进行影响,温度对于泥岩的内摩擦角没有明显直接的影响,但可以通过使泥岩含水率降低从而使内摩擦角增加。(4)通过模型试验,温度和含水率沿深度方向的梯度将泥岩按受到温度影响的不同分为三个层位,分别为：波动层、过渡层和稳定层。(5)温度场对于泥岩力学性能的直接影响有以下两点：在温度上升条件下,温度可以使泥岩的内聚力小幅增加,对于较深层的泥岩的增加效果相对明显；对循环温度场作用下,循环温越差大且温度变化越速率大时,泥岩力学性能的劣化效果越强。
[Abstract]:In Nanning area, there are many problems such as slope sliding, foundation pit collapse and foundation softening caused by the deterioration of mudstone, which cause great economic loss and some safety accidents. In previous studies, more attention has been paid to the results of water-rock interaction, while the process of temperature influence on soft rocks such as argillaceous rocks has been neglected, because the degree of temperature damage to argillaceous rocks is directly related to the effect of water-rock interaction. In view of the above factors, the model test and small sample test are used to analyze and study the influence of temperature on mudstone. Firstly, the distribution and variation trend of temperature field and water cut in mudstone under the influence of temperature field. The following small sample tests focus on the changes of the mechanical and hydrological properties of mudstone under different temperature conditions, and the results of the small sample tests are fed back to the model test. The comprehensive analysis shows that the influence of temperature on the mudstone in different depth and its variation rule. The conclusions are as follows: (1) the temperature holding capacity of mudstone depends on the water content of mudstone to a great extent, the surface mudstone is greatly affected by temperature, and the moisture content decreases as a result of the quick migration of water content out of the mudstone. With the decrease of specific heat capacity, the damage of mudstone is more likely to occur, while the deep mudstone is weak by temperature, and the water content changes little, and the specific heat capacity is relatively constant. The higher the temperature and the drier the mudstone (surface layer), the faster the mudstone (surface) sample collapses when it meets water. However, temperature has little effect on the disintegration rate of mudstone (deep layer) samples with high water content.) the effect of temperature on mudstone is mainly influenced by water as a bridge to the water content of mudstone. Thus, the mechanical and thermal properties and hydrological properties of mudstone are affected. The temperature has no obvious and direct effect on the angle of internal friction of mudstone, but it can increase the angle of internal friction by reducing the moisture content of mudstone and increasing the angle of internal friction. The gradient of temperature and water cut along the depth direction divides the mudstone into three layers according to the temperature influence, namely, the fluctuation layer, The direct effect of temperature field on the mechanical properties of mudstone is as follows: under the condition of temperature rising, temperature can increase the cohesion of mudstone slightly, and the effect on the deeper mudstone is relatively obvious; Under the action of cyclic temperature field, the degradation effect of mechanical properties of mudstone is stronger when the temperature difference and the temperature change are larger.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TU45

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