【作者】 蒋鑫；

【导师】 邱延峻；

【作者基本信息】 西南交通大学 ， 道路与铁道工程， 2005， 博士

【摘要】 近年来,随着我国交通设施基础建设的深入开展,高等级公路、铁路建设中更频繁地碰到了异型断面路基路面的修筑问题,但异型断面路基极易造成各类路基路面病害。从总体上看,国内关于异型断面路基路面整体设计的理论研究还处于起步阶段,严重制约异型断面路基上承路面工程的建设质量和建成后的长期使用性能。开展西南山区填挖过渡段路基路面整体设计方法的研究,对于提高路基路面结构设计水平,避免路基上承结构的早期破坏,保证路面使用寿命,都有重要的经济和技术意义。 本文在教育部优秀青年教师资助计划项目“异型断面路基路面综合设计理论研究”(项目编号:1900)、四川省交通厅科研项目“新老路基不均匀沉降对路面长期性能的影响”、西部交通建设科技项目“高原湿地郎川公路修筑及环境保护技术研究”(项目编号:200431800054-3)及铁道部科技发展计划项目“渝怀线斜坡软弱地基填方工程特性及工程技术研究”(项目编号:2001G011)等的资助下,对异型断面路基路面综合设计理论进行了较系统、深入的研究,主要研究内容有: (1)国内首次提出了异型断面路基的概念,将横向半填半挖路基、纵向填挖过渡式路基及纵横空间填挖过渡式路基三者定义为狭义的异型断面路基,广义的异型断面路基尚包括斜坡路基、旧路拓宽及桩基承台式路基等。从总体上看,异型断面路基具有一些共同特点:由于断面(包括横断面或纵断面)上几何或材料的异型,将导致断面上易产生差异变形(包括工后沉降和重复荷载作用下的永久变形),而差异变形将对上承结构(路面、轨道、道面)产生附加力学响应,直接导致上承结构的使用寿命大大缩减。 (2)结合国道108线广北段、四川绵广高速公路、318国道川藏线、109国道青藏线等实地路况调查及既有文献资料,详细论述了异型断面路基路面的病害现象及成因分析。异型断面路基路面病害的机理可以归纳为两大类:即路基稳定性不足导致的损坏和填挖方路基不均匀沉降引起的损坏。路基滑动和支挡结构破坏是稳定性不足的反映,而路面损坏的主要原因则是由于填挖方路基差异沉降引起。 (3)针对一横向半填半挖路基,运用强度折减法,基于FLAC/SLOPE Version 4.0软件平台,分析了因填挖结合部存在着的相对软弱带对路基稳定性的影响,全面探讨了破坏面性态、安全系数值随软弱带与地基粘聚力之比值更多还原

【Abstract】 Subgrade is an integrated part of pavement structures. Insufficient subgrade support always results in premature failure and excessive distress of pavements, especially in road-widening projects and mountainous areas where unconventional subgrades such as cut-fill sections and profiles constitute one of the major reasons of pavement failure. This dissertation reports a comprehensive research of engineering behavior of unconventional subgrades and influence on pavement responses supported by the Excellent Young Teachers Program of MOE, P.R.C. This study includes 7 parts as listed below.(1) It is the first time that the concept of "unconventional subgrade" is draw in domestic. Because of the geometry and material non-uniformity, the differential settlement of part-cut part-fill subgrade will cause additional mechanical response to effect the pavement. It is of great significance to study the problem of unconventional subgrade and establish the design system.(2) Pavement distresses in several highway routes in Sichuan and Tibet area of China with unconventional subgrades were conducted. Major types of distresses in those routes including Highway 108 (Section between Guanyuan and Qipanguan), Mian-Guan Express (from Mianyang to Guangyuan), Highway 318 and Highway 109 were identified.(3) Based on the software desktop FLAC/SLOPE Version 4.0, strength reduction technique (SRT) is conducted to analyze the failure mode of part-cut part-fill subgrade. Also commercial finite difference method program FLAC~3D is conducted to analyze the dynamic behavior of part-cut part-fill subgrade under the earthquake dynamic loading.(4) Based on literature review of a large number of relevant domestic and international research findings, the technical specification and pavement analysis computer program are summarized and disadvantages in the unconventional subgrade design are discussed in details.(5) Based on elastic layer system, a plane strain finite element model, which may compute the additional stress of asphalt pavement, is drawn to analyze the influences of the asphalt pavement deformation due to the differential subgradesettlements. Such as differential settlement value; length and pavement structure parameters; including the thick and modulus of surface layer and base layer are analyzed. Furthermore some advice to avoid premature distress is advanced.(6) A computer software called KENPAVE developed by Yang H. Huang; professor of Kentucky University; written for pavement analysis and design; is conducted to analysis the portland cement concrete pavement responses over part-cut part-fill subgrade existing initial gap.(7) The principle technical methods to avoid premature distresses of unconventional subgrade and pavements are advanced. It is the first time in domestic that geocentrifuge model tests are carried out to investigate the behavior of subgrade settlement behavior in road-widening engineering.更多还原