The first subgrade is a strip structure project. The geological conditions along the line are quite different, and the filler is uneven. Many areas are in the soil with poor engineering properties such as expansive soil, red clay, soft rock weathered residual soil, etc., affected by geographical and climate changes, and due to various technical levels, economic conditions and construction machinery and equipment, China's railway subgrade design usually adopts lower technical standards, and the construction quality is often lax, which leads to various requirements of railways. It has become a widespread, difficult-to-manage and frequent disease of subgrade, and in recent years, with the increase of train speed and the aggravation of subgrade stress level, subgrade diseases have become increasingly serious. Major changes in distribution and function. Due to the insufficient design capacity of existing railway subgrade, the dynamic stress generated by the train running speed under the action of small dynamic load leads to various diseases, or makes the existing diseases more serious, which seriously affects the safe operation of trains. Therefore, it is very important for the protection and management of subgrade to understand the types and mechanism of diseases and carry out actual detection.
Keywords: railway subgrade, disease, mechanism, detection
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