Bearing capacity analysis method for pre-drilled pile sinking foundation in dam area

Abstract

A bearing capacity analysis method for a pre-drilled pile sinking foundation in a dam area comprises the following steps: (1) layering a site stratum according to stratum formation causes, times, lithology and engineering characteristics of a construction site; (2) determining precast pile parameter values of different stratums; 3) setting a test pile area A and a test pile area B, arranging a plurality of test piles and anchor piles in the test pile areas, and estimating the compressive ultimate bearing capacity of all single piles to obtain an estimated value; 4) performing construction andstatic load test analysis to obtain a bearing capacity measured value of each single pile; 5) comparing the estimated value of each single pile with the measured value, and carrying out bearing capacity abnormity reason analysis on the single pile with large deviation between the measured value of the bearing capacity and the estimated value; (6) providing a calculation method which can consider the influence of the hole diameter and the hole depth of the pre-drilled hole and accurately estimate the single-pile bearing capacity; (7) providing a pile foundation bearing capacity model considering the stress diffusion theory to calculate a short pile estimated value, and (8) evaluating the pile foundation bearing capacity by adjusting the hole depth and the hole diameter of the pre-drilled hole.

Description

technical field [0001] The invention belongs to the technical field of engineering construction, and in particular relates to a method for analyzing the bearing capacity of pre-drilled pile foundations in the dam area. Background technique [0002] In order to fully consume the abundant renewable energy in the Zhangbei area, the State Grid invested in the construction of the Zhangbei Renewable Energy Four-terminal Ring Flexible DC Power Grid Demonstration Project. This project is the world's first DC grid with network characteristics. The flexible DC grid with the highest grid level and the largest transmission capacity has accumulated technical advantages for my country's flexible DC transmission in the development and utilization of new energy. Zhangbei Converter Station is one of the important node projects of this project. It is located in the Bashang plateau area. The site’s special rock and soil involve seasonal frozen soil, saline soil, expansive soil and weathered roc...

AI Technical Summary

Problems solved by technology

Zhangbei Converter Station is one of the important node projects of this project. It is located in the Bashang plateau area. The site’s special rock and soil involve seasonal frozen soil, saline soil, expansive soil and weathered rock. There are few people around the site, and there is no experience in similar projects. , which brings challenges to the geotechnical investigation and design of this project

[0003] In addition, the pre-drilling process will also have an impact on the bearing capacity of the pile foundation. For non-borrowing pre-drilling processes such as ramming or vibrating immersed tubes, it is beneficial to increase the bearing capacity because the soil around the pile is compacted, but for long-term Spiral soil pre-drilling, the undisturbed soil is taken out of the pile hole to cause stress release, which has a negative impact on the bearing capacity of the pile foundation

Soil pre-drilling can reduce the soil squeezing effect of the pile on the pile side soil, but it will relax the lateral horizontal force on the side of the hole, which is more likely to cause the weakening of the bearing capacity of the prefabricated pile. Insufficient attention has been paid to the impact of carrying capacity, and relevant theoretical research is also lacking

An empirical study shows that local construction of prestressed pipe piles with long spiral soil pre-drilled holes has little effect on the bearing capacity of pipe piles, but pre-drilled holes in expansive cohesive soil in the dam area have a greater impact on the bearing capacity of pile foundations. influences

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