【作者】 刘晓明；

【导师】 赵明华； 苏永华；

【作者基本信息】 湖南大学 ， 岩土工程， 2006， 博士

【摘要】 在我国中西部高速公路建设中存在大量红层软岩路段,该类岩石因其成因特殊而成分复杂且大部分具有崩解性,作为一种特殊路基填料使用往往导致工程建设成本高,施工进度缓慢。为此本文结合交通部“九五”行业联合重点攻关项目“京珠高速公路湘潭至耒阳段红砂岩地带路基修筑技术研究”,对红层软岩的崩解性、路用性能以及路基在汽车荷载作用下的动力变形特性进行深入研究。本文首先在大量工程调研的基础上指出红层软岩作为路基填料必须解决的两个关键问题,即其崩解性(崩解机理、崩解程度评价、崩解性消除方法等)和路用性(红层填料的可压实性、强度特性以及荷载作用下的变形特性等)问题。继而针对红层软岩及其崩解物进行了较全面的室内和现场试验研究。提出了红层软岩作为高速公路填料的可能性,并在此基础上制定出红层材料作为路基填料应达到的压实度水平。由于软岩崩解程度目前尚无合适的评价指标,本文引入分形理论对红层软岩的崩解分形机理进行了研究,深入探讨了崩解过程中崩解物粒度分布分数维的变化规律,并根据分形概念建立出红层软岩崩解过程的数学模拟模型,证明了红层软岩崩解是一个分形,在此基础上提出了对红层软岩崩解进度进行描述的新指标—粒度分数维,为工程应用提出了红层软岩作为路基填料所应达到的粒度分数维控制标准。此外,还从沉积岩土成因角度出发,改进了常用的粒度分布分形模型,使之更适用于沉积岩土的粒度分析。并将改进模型应用于崩解性差异显著的三类红层软岩的粒度特征分析,发现红层软岩的粒度特征可反映其崩解性强弱,从而提出了以粒度特征对红层软岩进行工程分类的思想,进而论证了公路工程中采用浸水崩解试验对红层软岩分类的合理性。然后,本文采用灰色关联度方法对红层软岩崩解影响因素进行了分析,结合本文试验和前人研究成果,较全面地分析了红层软岩的崩解机理。在此基础上,对包括抑制红层软岩崩解的添加剂、降低路基中干湿变化程度、人工加速红层软岩崩解进程等消除红层填料崩解性的多种路用控制方法进行了研究。提出了实用的红层软岩崩解性路用处治方法,并通过现场实验和工程实例论证了处治的必要性和可行性。为了进一步探讨红层填料路基在车辆动力循环荷载作用下的工作特性,本文建立出3轴9自由度车辆动力模型以及路桥过渡段路面形状模型,基于MARC有限元软件进行二次开发,得到了可用于分析汽车作用下路基动力响应的三维有限更多还原

【Abstract】 There are lots of expressway sections lay in red beds in the Central-Western of China. Soft rock of red beds contain complex ingredients and many kinds of these rock have the property of slaking which need higher budget and longer construction period when used as embankment filling material. So combined with the major joint research project sponsored by the ministry of communications“Research on the embankment construction technique in red beds belt of JIN-ZHU expressway XIANGTAN to LEIYANG section”, the slacking and engineering properties according with the dynamic deformation properties under vehicle repeat loading of red beds material are conducted in this paper.Based on the deeply survey on the road in red beds, the two key problem that using red bed soft rock as embankment filling material are pointed out, they are slaking properties including the slaking mechanism, evaluation method of slaking degree and elimination method further slaking, and the engineering properties of the soft rock material, including compacting properties, strength and deformation properties under vehicle repeat loading. Then, based on the field and laboratory experimental results on soft rock of red beds and its slaked material the possibility of using red bed soft rock as embankment filling material is advised and the compacting lever that those material should reached is suggested also.Since there is no suitable method on evaluating the slaked degree of red beds soft rock, fractal theory is introduced into analyzing the slake fractal mechanism of red beds soft rock. By deeply researching the granularity fractal characters variation regularity of the slaking material in different slake stage, an fractal index to evaluate the slaking degree of soft rock of red beds is derived. A numeric model to simulate the slake process of soft rock is established based on fractal concept. Simulation proved the feasibility of evaluation the slaking degree of soft rock by using fractal index.Further more, based on analysis of the formation process of sedimentary rock and soil, a improved fractal model of granularity distribution was conducted in this paper which is more suitable for sediment granularity distribution analysis. Application of the improved model on analyzing the granularity distribution of three kinds of red beds soft rock with notable differentia on durable property show that the granularity fractal characters of red beds soft rock can reflect the durable property of the rock. So the idea of red beds soft rock should be classified by its granularity fractal characters is suggested and then the the rationality of using soak test as engineering classify method on red beds soft rock is proved.Based on the influence factors of slacking property of red beds soft rock analysis by using the grey correlation method, combined the existing research results, the slacking mechanisms are analyzed, and the special slacking mechanisms distinguish更多还原