Tan Heng West Highway Retaining Structure Of The Field Test And Design Methods

As Xiangtan to Hengyang express highway cross the red sandstone,slope protection engineering has huge amount of work and must pay attention to the ecological protection.So far,the combining form of supporting and retaining structure and ecological slope protection is single in common use at home and abroad.By comprehensive consideration,three new type support structures-compound reinforced gabion retaining wall, geogrid reinforced earth retaining wall(flexible mess), reinforced gabion abutment were adopted.Therefore,the study on the engineering geological characteristics of red sandstone,the material properties of new type geosynthetics,the interaction characteristics between reinforced materials and soils and the design and construction technology of reinforced gabion retaining wall, have important significance in study,design,construction and application of this new geosynthetics and new type support structure.Combining scientific research task supported by Hunan provincial communications department and science & technology department-the technology research on these new type reinforced earth structures and the demonstration project in Xiangtan to Hengyang express highway in Hunan province,a series of soil test,field tests and theoretical analysis were carried out.And this article comprehensively and systematically analysed this new reinforced earth technology,providing basises and references for design and construction the same type reinforced earth retaining wall.The main couclusions were as follows:1. The engineering characteristics of red sandstone was concluded and summarized.By the ways of field sampling and the horizonal push-shear in-situ tests, the major physics and mechanics indexes of red sand silty clay were obtained.Large-scale triaxial tests were carried out and the characteristic of strength and the deformation of reinforced and non-reinforced red sandstone soil with different reinforcement layers, different compaction and different water content, were studied. This paper analyzed the feasibility of red sandstone as a filling on the basis of construction technology.2. Engineering background and material properties were introduced in detail.Combined with the laboratory model tests, the tensile test of gabion and geogrid and the pull-out friction test of reinforced earth, the physical and mechanical characteristics of gabion and geogrid and the interaction characteristics between reinforced materials and soils, has been studied deeply.And This paper deeply researched the durability of the reinforced gabion material and its influencing factors.3. Components, technical features of the gabion structure and its composite structures, geogrid reinforced earth retaining wall (flexible mess), reinforced gabion abutment were presented. Based on the engineering geological conditions of the test section, systematic in-situ testing scheme was established.And the distribution and variation law of the lateral pressure on the facing, the vertical earth pressure with filling height and time, the tied-reinforcement and gebion deformation, the shape of rupture surface and the horizontal deformation of face panel of the wall, were studied through on-site monitoring three typical sections of Xiangtan to Hengyang express highway in Hunan province. The working mechanisms of three new supporting and retaining structures were sufficiently studied.4. Components, technical features, and design method of the reinforced gabion retaining wall were analyzed and summarized.Combining with practical project, the application of deterministic design method (Safety factor method) and structural reliability theory (Rosenblueth method) in the stability analysis of the reinforced gabion retaining wall were studied by means of relative program. Finally, the influences of parameters of shear strength on the stability of reinforced gabion retaining wall were deeply discussed.