| The area of seasonally frozen soil in our country is huge,and the high-speed rail business is booming.There are more than 35,000 kilometers of high-speed railways in use in our country,and the use of it in cold regions is also increasing year by year.Zhangjiakou is a seasonal frozen soil area.At the same time,it will inevitably promote the development of high-speed rail in the Zhangjiakou area with the completion of the Jing-Zhang railway.It has very strict standards for the deformation and stability of the line.With the changes in the four seasons,the high-speed railway foundation will have a decrease in durability,which will affect the normal use of high-speed railways.Starting from the surface of the bed of the high-speed railway base,the coarse particle filler is used as the object to improve it.This paper mainly conducts water stability test,freeze-thaw durability test and one-way freeze-thaw cycle test,and studies the mechanics and frost heave-thaw characteristics of coarse-grained fillers.First,we determine the basic indicators of the test aggregate and analyze the improvement mechanism of the modifier.Secondly,Through the first two experiments,we can get the mechanical properties of the improved coarse-grained filler and its improved performance.Combined with the theoretical analysis method of gray correlation,we can determine the types of improved coarse-particle fillers with better mechanical properties,and use this as the basis for subsequent experiments.Finally,through the last experiment,we can get the frost heave and thaw settlement characteristics of the improved coarse-grained filler and its improved performance.This can strive to provide value for the application of high-speed railways and related projects.The main content is divided into the following points:(1)The basic physical performance test of some components of the coarse particle filler tested,mainly include and the content test of needle-like particles of coarse aggregate,the liquid plastic limit test and compaction test of fine-grained soil.The index of the aggregate in the filler is determined.It can prepare for the subsequent test.(2)Determine the type of inorganic modified materials tested,and analyze the improvement mechanism of the selected inorganic modified materials;Design the gradation of the filler through specifications and use the equivalent replacement method to reduce the particle gradation of the filler;Through the compaction test of each filler,we can obtain the effect of the modifier in the compaction characteristics of coarse-grained fillers.(3)The study of mechanical properties is carried out through water stability test and freeze-thaw durability test.The water stability test has three factors: curing age,immersion condition and filler type.The freeze-thaw durability test has three factors:the curing age,the number of freeze-thaw cycles and the type of filler.And then compares and analyzes the improved characteristics of the improved coarse-grained filler.(4)By combining the gray correlation analysis method with the mechanical indicators in(3),we can determine the types of improved fillers with better improved properties in the mechanical properties.This is used as the basis for subsequent experiments.(5)Select the type of improved filler determined in(4),and use the one-way frost heave and thaw sedimentation test to deeply analyze the improved characteristics of the improved coarse-particle filler in terms of frost heave and thaw sedimentation characteristics under the conditions of repeated freezing and thawing in one-way.Then compare and analyze the improved characteristics of improved coarse-grained fillers to provide a basis for engineering construction and design. |
PDF Full Text Request