客运专线土工格室复合基床的试验研究

研究目的:在列车荷载的重复作用下,基床结构永久变形是轨道结构几何尺寸恶化的重要因素之一。采用土工格室复合基床结构可以强化基床表层强度和刚度,以满足特殊路段基床结构的需要。研究方法:本文介绍了适用于客运专线的土工格室复合基床结构的4组动态模型试验。试验在室内填筑了宽7m、长4m、高1．05-1．55m的路基基床模型,采用5 Hz、20-140kN动荷载模拟列车荷载,每组重复加载150万次以反映列车对路基基床的重复荷载作用。为验证室内试验结果,在秦沈线进行了现场动态试验。试验结果表明, 土工格室可均化基床、路基的动静应力分布,明显降低基床和路基的弹性和永久变形,减少运营维修养护工作量,且格室越高效果越好。研究结论:通过与现场试验结果对比,30 cm厚的土工格室复合基床表层基本能够满足客运专线对基床刚度和变形控制的要求。

EXPERIMENTAL RESEARCH ON THE GEOCELL OF COMPOUND SUBGRADE-BED FOR PASSENGER DEDICATED RAILWAY LINE

Research purpose: The permanent deformation of the the subgrade-bed under the repeated loading of the train deteriorate the truck state. Increasing the strength and the stiffness of subgrade-bed can abate the demage. Research method: In this paper, 4 group of model tests are carried out under the simulated field conditions to study the dynamic performances of the subgrade-bed for passenger dedicated railway line with different thickness and reinforced with the geocell. The length,width and height of the model is 7 m,5m and 1.05-1.55 m. In order to simulate the action of the passenger dedicated railway line wheel load on the subgrade bed, the 5Hz cyclic loading is repeated 1.5 million times in every group of test. Research result: In order to compare the model tests, the test in situ were carried out. Refer to the subgrade-bed without geocell, the dynamic stress of the sugrade bed with geocell is smaller and more uniform, the elastic deformation and the permanent deformation decrease obviousely. Research conclusion: By comparing with the live model tests, the strength and the stiffness of the subgrade-bed with geocell which thickness is 30cm can satisfy the demands of the passenger dedicated railway line