Construction method of graded broken stone and cement composite packing layer

Abstract

The invention discloses a construction method of a graded broken stone and cement composite packing layer. The construction method includes watering to cover and maintain after filling and grinding of graded broken stone and cement filler meet the compacting standard; detecting the setting and hardening degree of the packing layer after a day, detecting dynamic deformation modulus Evd, the foundation coefficient K30 and / or secondary deformation modulus Ev2 indicators of the packing layer by a test instrument, grinding in a vibration manner by a road roller adopting filling and grinding if the indicators are up to the set values, so that the packing layer can generate map cracks so as to eliminate partial shrinkage stress generated by drying shrinkage and temperature shrinkage of the graded broken stone with the cement, and serious shrinkage cracks are avoided; stopping grinding if the indicators reach 55-65% of the preset value before vibratory grinding; watering again to cover and maintain for seven days or paving geogrid on the packing layer after the cracks are healed automatically, and paving, grinding, maintaining, cracking and constructing on the former layer. The construction method can control shrinkage cracks of the graded broken stone with the cement and is applicable to filling and construction of filler of the graded stone with the cement in different mixing amounts.

Description

technical field [0001] The invention relates to a railway embankment engineering construction technology, in particular to a construction method for graded crushed stone mixed with cement filling layer. Background technique [0002] In the construction of railway subgrade engineering, in order to ensure the strength, stiffness and water stability of the subgrade, the transition section of the subgrade and the surface of the subgrade bed of the high-speed railway are usually filled with graded crushed stone mixed with cement. At the junction of the railway subgrade and the bridge, due to the great difference in stiffness between the subgrade and the bridge, it will inevitably cause a sudden change in the stiffness of the track. Near the transition point of the road and bridge, it is easy to produce poor deformation, which will affect the smooth and safe operation of the train. In order to reduce the deformation difference between roads and bridges and gradually change the tra...

AI Technical Summary

Problems solved by technology

However, the existing railway subgrade transition section and subgrade surface diseases show that the current construction methods and measures for graded gravel mixed with cement filler are difficult to avoid the drying shrinkage and temperature shrinkage of graded gravel mixed with cement filler. characteristics, often lead to shrinkage cracks in the filling layer, affecting its normal use function

Images