压实土体崩解特性试验研究

发布时间：2019-02-21 16:07

【摘要】：长江上游地区的涉水岸坡,由于自然因素,随着水位的涨落,岸坡土体经历“浸水—风干—浸水”的过程,岸坡土体易发生崩解,崩解后的土体散落于水中,在水下自然堆积,造成河道淤堵、阻塞航道等不利影响。压实土体崩解的发生、发展的过程实际上是压实土体颗粒间的力学变化过程。为了研究压实土体崩解机理,本文依托国家自然科学基金项目(No.51479012)“周期性饱水砂泥岩混合料的劣化机理及其演化过程”开展研究工作,自主研制了室内压实土体崩解及水下休止角联合试验装置,通过系列试验研究了压实土体的崩解特性及水下休止角变化规律等,主要研究内容与成果如下:(1)基于传统崩解试验方法精度较低的问题,研制了一套压实土体崩解试验系统。该系统可对压实土体崩解过程中的试样质量变化、体积变化、崩解速度、崩解时间和崩解完成后土体在水下堆积出的水下休止角进行有效监测。(2)查明了压实土体试验中崩解时间的变化规律。利用自主研制的试验装置,开展了崩解试验研究,分析了含水率、密实度、颗粒级配、颗粒种类等因素对压实土体崩解时间的影响。基于崩解过程中的试验现象,结合压实土体崩解时间的变化规律,分析了影响砂岩、泥岩、砂泥岩混合颗粒土料崩解时间的主要因素。(3)查明了压实土体试验中崩解量的变化规律。基于自制试验系统,开展了不同含水率、密实度、颗粒级配、颗粒种类下的崩解试验,获得了各因素下的崩解指标,分析了崩解量与各因素的规律。基于试验结果,探讨了影响不同颗粒种类土料崩解量的主控因素。(4)查明了压实土体试验完成后水下休止角的变化规律。根据试验中崩解结束后圆盘中堆积土丘的高度,计算出崩解土体形成的水下休止角,获得了含水率、密实度、颗粒级配、颗粒种类等因素对于水下休止角的影响,明确了水下休止角与崩解量、崩解时间之间的关系,基于试验结果,探讨了影响水下休止角的主控因素。
[Abstract]:In the upper reaches of the Yangtze River, due to natural factors and with the fluctuation of the water level, the slope soil experienced the process of "soaking, air drying and soaking", and the soil on the bank slope was prone to collapse, and the soil was scattered in the water after disintegration, and accumulated naturally under the water. Cause channel blockage, block channel and other adverse effects. The process of collapse and development of compacted soil is actually a process of mechanical change between particles of compacted soil. In order to study the collapse mechanism of compacted soil mass, this paper relies on the project of National Natural Science Foundation (No.51479012), "deterioration Mechanism and Evolution process of periodically saturated Sand and mudstone mixture". In this paper, a self-developed laboratory test device for compacted soil mass disintegration and underwater angle of repose is developed. The disintegration characteristics of compacted soil and the variation of underwater angle of repose are studied through a series of tests. The main research contents and results are as follows: (1) based on the low precision of traditional disintegration test method, a set of compacted soil disintegration test system is developed. The system can deal with the mass change, volume change and disintegration velocity of the sample in the process of compacting soil mass disintegration. The disintegration time and the underwater angle of repose accumulated under water are effectively monitored. (2) the variation law of disintegration time in compacted soil test is found out. In this paper, the disintegration test was carried out by using the self-developed experimental device, and the effects of water content, compactness, particle gradation and particle type on the disintegration time of compacted soil were analyzed. Based on the experimental phenomena in the process of disintegration, combined with the rule of the disintegration time of compacted soil, the influence of sandstone and mudstone is analyzed. The main factors of the disintegration time of sand and mudstone mixed granular soil material. (3) the rule of the quantity of disintegration in compaction soil test is found out. Based on the self-made test system, the disintegration tests under different moisture content, compactness, particle gradation and particle type were carried out, and the disintegration indexes under each factor were obtained, and the disintegration quantity and the law of each factor were analyzed. Based on the experimental results, the main controlling factors affecting the amount of soil collapse of different particle types are discussed. (4) the variation law of underwater angle of repose after the completion of compacted soil test is investigated. According to the height of the accumulated mound in the disc after disintegrating, the underwater angle of repose formed by the disintegrating soil is calculated, and the effects of water content, compactness, particle gradation and particle type on the underwater repose angle are obtained. The relationship between the angle of repose under water, the amount of disintegration and the time of disintegration is clarified. Based on the experimental results, the main controlling factors affecting the angle of repose under water are discussed.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU43

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