Study On Design Method Of Reinforced Soil Structure Based On Cable Theory Under Non-uniform Settlement Condition

Uneven settlement is a common engineering disease at soft soil foundation or the junction of old and new foundation,due to consolidation settlement,rainfall or earthquake.It is commonly used in engineering to adjust the uneven settlement by using reinforced soil structure.However,at the present stage,there are few theoretical studies on the stress and strain of reinforced material while the reinforced soil structure is under the condition of uneven settlement,and the engineering practice is often preceded by theoretical research.In order to improve and simplify the design theory of reinforced earth structure,based on cable theory,the stress and strain of reinforced material in reinforced soil subgrade and reinforced earth retaining wall are theoretically derived by using rigid cable theory and elastic cable theory as the reinforced material in reinforced soil structure being considered as the research object,to obtain the force and deformation law of reinforced material under vertical uniform load.The feasibility and accuracy of theoretical research results are discussed in combination with laboratory model tests.Combined with the results of this study,the main conclusions are as follows:(1)Aiming at the uneven settlement of reinforced soil subgrade,the rigid cable theory is applied to the reinforced soil structure,and some basic assumptions about the rigid cable theory are made in combination with the engineering practice,then the rigid cable theory is revised,and a set of theoretical methods for calculating the deformation law of reinforced materials is proposed for the first time.(2)The indoor model test of reinforced soil subgrade is carried out: the building materials are used to simulate the rigid structures such as the bridges and culverts,alternately laying the sliding board and the rigid roller is used to simulate the subgrade,polyester fabrics are used to simulate the reinforced materials,and simulating the settlement by twitching skateboard slowly.The test results show that the deformation law of the reinforced materials is basically the same as that predicted by the modified rigid rope theory;there is a certain stress relaxation in the reinforced material during the test,it is found that the relaxation phenomenon of the reinforced material gradually disappears with the increase of the uneven settlement,and the final result of the test is close to the theoretical result.(3)Aiming at the phenomenon that the stress concentration,fracture and separation is easily occurred in the connection between the panel and the reinforced material of the reinforced earth retaining wall under the uneven settlement,the elastic cable theory is modified to analyze the stress and strain at the junction of the retaining panel and the reinforced material,and the corresponding theoretical methods are proposed for calculating the stress and strain of reinforced concrete retaining walls under the confined and unconfined conditions for the first time.(4)Indoor model tests which use gauze net to simulate reinforcement material,simulate the retaining wall with sliding board,take tempered glass as observation device,and lifting Jack as settlement device of reinforced earth retaining walls under confined and unconfined conditions were carried out respectively.The test results show that the stress and deformation laws of reinforced materials in tests are basically consistent with those predicted by the modified elastic cable theory.