Design Method for Slab Column Foundation of Transmission Circuit in Cohesive Soil

Abstract

The invention relates to a design method of a power transmission circuit board column foundation in clayed soil. The design method comprises the following steps: (S1) a buried depth and a bottom width in present calculation are determined; and a depth-to-width ratio of the foundation is calculated; (S2) the shear strength of the soil is calculated; and a limit value of the depth-to-width ratio of the foundation is further calculated; (S3) intermediate parameters alpha and beta are calculated based on the depth-to-width ratio of the foundation and the limit value of the depth-to-width ratio of the foundation, wherein the value of the intermediate parameter alpha is not higher than 1; (S4) destruction factors are calculated based on the parameter beta; (S5) the uplift bearing capacity is calculated based on the destruction factors, the shear strength of the soil, the area of a baseplate, the weight of the soil, the buried depth and self weight of the board column foundation; and (S6) the uplift bearing capacity and the uplift load are compared; and the finite element analysis is performed. The method is reliable and reasonable and accurate in calculation results, and improves the design safety and economy of the power transmission circuit board column foundation.

Description

technical field [0001] The invention relates to the technical field of electric power, in particular to an accurate calculation method for designing slab-column foundations in cohesive soil for transmission lines. Background technique [0002] The transmission tower foundation is an important part of the transmission line, and its project cost, construction period and manpower consumption account for a large proportion of the entire line project. The slab-column foundation is one of the most commonly used types of railway tower foundations, and is widely used in domestic and foreign railway projects. [0003] Burial depth and floor width are important parameters in the design of slab-column foundations, which directly determine the uplift bearing capacity of the foundation. At present, my country's power industry standard "Technical Regulations for Overhead Transmission Line Foundation Design" DL / T 5219 (hereinafter referred to as "Technical Regulations"), the US "IEEE Guid...

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Problems solved by technology

However, the "failure factor theory" calculation formula based on the anchor plate pullout model (hereinafter referred to as the original calculation method) cannot be directly applied to the pullout design of transmission line foundations.

The original calculation formula of foreign scholars has great limitations: (1) The original calculation method is derived based on the uplifting test data of the anchor plate in saturated clay. Whether the above theory is applicable to the large-scale power transmission line slab-column foundation requires the true shape of the slab-column foundation The test and the verification of finite element data; (2) The intermediate parameters of the original calculation method did not give the calculation method, which can only be measured through graphics, which is inconvenient to use; (3) The soil used for the anchor plate pull-out test is saturated cohesive soil , the strength adopts the undrained shear strength C u , but the foundation soil of the transmission circuit board column is backfill soil, the soil is unsaturated cohesive soil, and there is no undrained shear strength C u

The original calculation method did not give the cohesion c and internal friction angle of the soil and other parameters are calculated to obtain the uplift bearing capacity, buried depth and floor width required for the design of the slab-column foundation

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