【作者】 高志超；

【导师】 陈忠达；

【作者基本信息】 长安大学 ， 道路与铁路工程， 2011， 硕士

【摘要】 路基是路面结构的基础,坚固而又稳定的路基能为道路长期承受车辆荷载提供重要保证。而路基的强度和稳定性是与路基填料的CBR值密切相关的,但有些路基填料(如黄土、与黄土性质相类似的低液限黏土等)的CBR值往往无法达到规范的要求(尤其是高等级公路上路床),却在保证施工质量的前提下,路基仍然具有良好的路用性能,能够满足高等级公路的使用要求,由此可知,规范对CBR值的要求并不适用于这些路基填料,为此,针对这些特殊的填料研究制定合理的CBR值标准是十分必要的。本文首先对路基填料强度特性以及各项力学控制指标(抗剪强度、压缩模量、无侧限抗压强度、地基反应模量以及CBR值等)进行研究,分析了以CBR值作为路基填料的力学控制指标的合理性；其次,通过室内外试验并结合理论指导,分析了CBR试验机理与试验条件；另外,利用大量的试验分析了河北省衡大高速公路路基填料CBR值的影响因素(颗粒粒径、矿物组成成分、压实度、路基含水率和浸水时间等),同时,建立了路基填料CBR值与压实度和回弹模量之间的关系；基于以上的研究分析,并结合理论及高等级公路路基填料CBR值的统计结果,制定出缩短CBR试验浸水时间的路基填料力学控制标准1和降低规范对CBR值要求的路基填料力学控制标准2；最后,探讨了路基填料CBR值的提高方法。研究成果对高等级公路设计和施工具有重要的参考价值。更多还原

【Abstract】 Sub-grade which is solid and stable is the basis for the pavement structure that can withstand traffic loads for the road and provides an important long-term guarantee. However, the strength and stability of Sub-grade has the closely related with CBR value of Sub-grade Filling, but the CBR value of some Sub-grade Filling(such as loess, low liquid limit clay with the loess properties etc.) are often unable to meet the Standard(especially the road bed of the highway), However, the premise of ensuring the quality of construction, the Sub-grade still has a good road performance and can meet the application requirements of highway. It can be seen that the Standard for CBR value requirement of Sub-grade Filling does not apply to the Sub-grade Filling, Therefore, it is necessary for these special filling to establish a reasonable standard of CBR value.Based on the strength properties and the contrast among various mechanical control indexes(shear strength, constrained modulus, unconfined compression strength,foundation modulus California Bearing Ratio etc.) of Sub-grade Filling, the paper firstly analysises CBR as the control index is reasonable and feasible; Secondly, through the the indoor and outdoor experimental and theoretical analysis, we analyzed the mechanism and conditions of CBR test. In addition, we used a lot of test to analyze value of the factors (particle size, mineral composition, degree of compaction, moisture content of Sub-grade, Soaking time etc.) of the Sub-grade Filling CBR. Furthermore, we established the relationship among CBR and degree of compaction and modulus of resilience of Sub-grade Filling. Based on the above study and analyze, it is combined with the theoretical instruction and on the statistical of CBR value of the highway Sub-grade Filling,we work out mechanical control of standard 1 of Sub-grade Filling which is shorten the soaking time of the CBR test and mechanical control of standard 2 of Sub-grade Filling which is reduced the CBR value of the Standard; Finally, we have a discussion of the methods to improve the CBR value of the Sub-grade Filling.更多还原