【作者】 丁兆民；

【导师】 谢永利；

【作者基本信息】 长安大学 ， 道路与铁道工程， 2009， 博士

【摘要】 盐渍土作为一种特殊土，在环境条件变化过程中，由于土体中盐碱成分的迁移和聚集，反复结晶与溶解，积盐与脱盐过程的频繁交替与反复，使其表现出特有的工程特性，对工程建设有着不同程度的影响，如果不处置或处置不当将对工程建设的产生极大的危害。嘉峪关至安西一级公路沿线广泛分布有盐渍土和盐渍化软弱土，由于盐渍土工程性质比较特殊，如何有效地进行盐渍土地段路基设计，确保公路建设质量和公路建成营运后的长期稳定性，是嘉安一级公路建设中亟待解决的关键技术问题。本文以嘉峪关至安西一级公路盐渍土地段为试验研究依托工程，针对该盐渍土地段的工程特性和路基稳定性技术展开研究工作。通过系统的基本土工试验研究了盐渍土的工程特性及相关路基修筑技术，分析了盐渍化软弱土地基的特殊性质及其物理力学性质的影响因素和变化规律；根据室内试验和现场原位测试结果，总结了盐渍化软弱土的工程特性，选取的振动沉管挤密砂石桩和强夯加固是经济合理的地基处治措施，取得了良好效果；将均匀设计方法和冻融循环试验相结合，从土、水、盐、温、力五个方面对粗颗粒盐渍土的盐胀特性进行了深入研究，依据粗颗粒硫酸盐渍土依然可以在温度降低的过程中发生土体缩减现象，给出了粗颗粒盐渍土作为路基填料的可用性指标；分别采用石灰、石灰+粉煤灰、石灰+粉煤灰+水泥作为改良剂进行了盐渍土路基填料的改良试验，研究改良盐渍土的力学性能和路用性能，给出了施工技术要点；根据盐渍土路基中不同隔断层的特点和结构适应性，提出了隔断层设计优化设计及施工控制措施，通过进一步试验和数值仿真计算，分析了路基在冻融条件下的受力与变形特性及稳定性，提出了盐渍土地段路基合理断面型式。更多还原

【Abstract】 As a kind of special soil, salty soil could perform some distinctive project characteristics because of the transference and gathering, crystallization and dissolution and the frequent interchange and repetition process of salification and desalination of the ingredient of salinity and alkali during the change of environmental condition, which could have different effects to project construction, for instance it would cause extremely harm to the construction if it was untreated or treated improperly. There are plently of salty soil and saline soft soil along the first-class highways of Jia Yu-guan to An Xi, so it’s the key technical problem to be solved that how to effectively design the subgrade of saline soil road according to the special project characteristcs of salty soil so that ensure the construction quality and long-time steady during later operation.The paper work on the study of salty soil’s project characteristics and stability technology of subgrade which rely on the first-class highways of Jia Yu-guan to An Xi as the experimental project. Through the basic geotechnical test, saline soil project characteristic and the related subgrade construction technologies were studied and the influencing factor and the change rule of saline soft soil foundation’s special nature and the physical mechanics nature were analyzed; According to the laboratory test and the scene home position test result, the saline soft soil project characteristics were summarized, and found that the selections of vibrosinking sand-gravel compaction pile and dynamic consolidation method were the economical reasonable ground processes measures which has obtained a good result; Through the uniform design method and the thaw-freeze cycle experiment, the coarse-grained saline soil’s salty bulge characteristic were deep researched from five aspects which were the soil, the water, the salt, temperature, the strength, and given the applicability index of coarse-grained salty soil embankment filling according to the fact that coarse-grained salty soil still had reduce phenomenon in the process of temperature drop; Main techniques for construction were offered through the improved experiments of filling materials for subgrade which used lime, lime and coal ash, and lime, coal ash and cement as the modifier and the study to improved the mechanical properties and long term performance; Optimal design of insulating layer and building control methods were offered according to traits of different insulating layer and construction adjustability in the saline soil subgrade. The proper type of cross section of saline soil road subgrade was put forward through further experiments and the caculation of numerical simulation in thaw-freeze cycle condition.更多还原