Calculation method for ascending and descending amount of top face of low embankment of ballastless track under expansion-shrinkage action of expansive soil foundation

Abstract

The invention relates to a calculation method for ascending and descending amount of a top face of a low embankment of a ballastless track under the expansion-shrinkage action of an expansive soil foundation, so as to reasonably determine the ascending and descending amount of the top face of the low embankment under the expansion-shrinkage action of the expansive soil foundation in the flooding period, rainy seasons, dry seasons and the like, and provide bases for design of the low embankment of the ballastless track in the expansive soil zone. The calculation method is simple, easy for obtaining parameters, clear in physical meaning and capable of adapting to actual engineering demands. The method includes the following steps: (1) modifying the cross section of the rear low embankment by considering influence of the depth-width ratio of the embankment; (2) adopting the Boussinesq theory to calculate additional stress on the foundation under the modified low embankment load, and determining a modified low embankment calculation model; (3) calculating the ascending and descending amount of the top face of the low embankment under the expansion-shrinkage action of the expansive soil foundation by taking into consideration the 'compression' effect and 'unloading arch' effect of a low embankment body under the expansion-shrinkage action of the foundation.

Description

technical field [0001] The invention relates to the technical field of high-speed railway low embankments, in particular to a method for calculating the lifting amount of the top surface of a ballastless track low embankment under the expansion and contraction of an expansive soil foundation. technical background [0002] With the development of high-speed railway, the speed of train operation and the standard of railway construction have been continuously improved, and the deformation problem has become a controlling problem of foundation treatment. For expansive soil, in addition to the compression deformation under the action of external load, the expansion and contraction deformation of water-soaked expansion and dehydration contraction is also one of its important deformation characteristics, which is also an important characteristic different from ordinary soil. In general railway engineering, the expansion and contraction deformation of expansive soil foundation has r...

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Problems solved by technology

However, the transmission mechanism of expansion and contraction deformation of expansive soil foundations in flexible foundations (such as railways and highway subgrades) is not yet clear, that is, the amount of ups and downs of the top surface of flexible foundations is different from the amount of expansion and contraction of the foundation surface. The applicability of the expansion and contraction deformation calculation method recommended in the Technical Code for Buildings in Land Areas to the calculation of the lifting and lowering of the top surface of flexible foundations needs to be further demonstrated

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