Anti-heave design method of expansive soil composite pile foundation at the bottom of subgrade

Abstract

A heave-resistant design method of expansive soil composite pile foundations at the bottom of a subgrade comprises the steps of determining a design target, surveying geotechnical parameters, initially selecting and determining composite pile foundation parameters, determining calculation parameters, calculating a heave amount of the top surface of the subgrade, and determining composite pile foundation design parameters. The heave-resistant design method of the expansive soil composite pile foundations at the bottom of the subgrade comprehensively considers three factors of a composite pile foundation replacement function, a side surface anchorage function and a subgrade soil-filling energy-dissipation effect. The heave-resistant design method is proposed on the basis of taking the heaveamount of the top surface of the subgrade as a design control target, and is capable of scientifically and reasonably carrying out the heave-resistant design of the expansive soil composite pile foundations, effectively controlling the number of foundation reinforcement engineering, achieving the goal of reducing the railway construction cost, making up for the blank of specifications and adaptingto actual engineering needs.

Description

technical field [0001] The invention relates to the technical field of geotechnical engineering foundation treatment, in particular to an anti-uplift design method for expansive soil composite pile foundations at the bottom of roadbeds. [0002] technical background [0003] Unsaturated expansive soil has the characteristics of uplift and deformation when it encounters water. When building high-standard ballastless railways in similar areas, the uplift deformation of the foundation can easily lead to cracking of ballastless track slabs of high-speed railways, causing major ballastless track diseases, and even endangering high-speed railways. The driving safety of the train, especially the low embankment or cutting bed of the ballastless track. In order to weaken or eliminate the uplift deformation of the expansive soil of the subgrade base of the ballastless track, composite pile foundations (such as CFG piles, plain concrete piles, reinforced concrete piles, etc.) It can ef...

AI Technical Summary

Problems solved by technology

The Chinese utility model patent with the notification number CN204356594U discloses a ballastless track expansive soil cutting-bed structure. The main purpose of the patented cutting base using composite pile foundation reinforcement is to weaken or eliminate the uplift deformation of the expansive soil foundation, but the composite The determination method of the key design parameters of pile foundation (such as pile length, pile diameter, pile spacing, etc.) has not been explained, and there are no relevant specifications, documents or patents to mention it

It can be seen that when constructing high-standard ballastless track subgrades in expansive soil areas, there is still a lack of relevant anti-heave design methods for composite pile foundations, which is a key technical problem to be solved urgently

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