Deep-buried piles and their embedding methods for plane elevation control points in freeze-thaw areas

Abstract

The invention relates to a deep-embedded pile for plane vertical control point at a freeze-thaw area and an embedding method of the deep-embedded pile. A marker post consists of a steel protection tube and a cement protection tube at the upper part of the marker post, a fine-sand filled layer between the steel protection tube and the cement protection tube, a slide structure between the steel protection tube and the marker post, a cement-mortar protection layer of the marker post, a button stem and a slurry surface layer. The embedding method comprises the steps of upper pile hole excavation, cement protection tube embedding, drilling, marker post placement, cement mortar filling, slide structure arrangement, fixed base point mark measuring and the like. The tangential frozen-heave force can be reduced obviously by the slide structure of the deep-embedded pile, the cement-mortar protection layer of the marker post which is capable of removing bad holes, and the button stem of the marker post. The frozen-heave phenomenon is almost not generated in the fine-sand filled layer in the freezing process in the condition of fully water-saturation. The test proves that the thaw settlement amount can be controlled within the permissible range in both of the thaw area and the strong thaw area by using the deep-embedded pile, especially the embedding depth of the marker post can be adjusted to the gravel soil layer under the freezing depth according to the freezing depth, and the tangential frozen-heave force of the embedding depth of the marker post is nearly close to zero.

Description

technical field [0001] The invention belongs to a three-dimensional reference facility for ballastless track laying and operation and maintenance, in particular to a deep-buried pile of a plane elevation control point in a freeze-thaw area and a laying method thereof. Background technique [0002] In the existing technology, the measurement mark of the plane elevation control point is fixed on the mark stone. The method of laying the mark stone usually adopts the main steps of excavating the foundation pit → pouring cement → placing the base point mark stone → cement solidification and maintenance. The standard stone specification requirement is: 30cm at the top ×30cm, bottom 50cm×50cm, the marker stone is buried 0.5m below the permafrost layer. [0003] However, the above-mentioned marking stones and their embedding methods cannot be used in freeze-thaw areas where the groundwater level is high (1-2m), the permafrost layer is thick (2-2.7m), and the evaporation in spring an...

AI Technical Summary

Problems solved by technology

[0003] However, the above-mentioned marking stones and their embedding methods cannot be used in freeze-thaw areas where the groundwater level is high (1-2m), the permafrost layer is thick (2-2.7m), and the evaporation in spring and autumn is dry and windy, and the evaporation is about three times greater than the precipitation. Ensure the stability of base point measurement

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