Construction Method of Mechanism Model of Prestressed Anchor Cable Force Transmission when Anchor Section Crosses Double Strata

Abstract

The invention provides a method for constructing a mechanical model of the force transmission mechanism of the prestressed anchor cable when the anchorage section passes through double strata, and makes rational assumptions about the actual working state of the prestressed anchor cable; Classification; establish the equilibrium differential equation of the prestressed anchorage section in all elastic stages; deduce the shear stress distribution function and the range of pull-out force of the prestressed anchorage section in all elastic stages; deduce the partial yield in the first stage The distribution function of the shear stress and the range of the pull-out force in the anchorage section of the prestressed anchor cable; the distribution function of the shear stress and the range of the pull-out force in the anchorage section of the prestressed anchor cable during the second stage of partial yielding; The shear stress distribution function and the range of the pull-out force of the anchorage section of the prestressed anchor cable; the derivation of the shear stress distribution function and the range of the pullout force of the anchorage section of the prestressed anchor cable at the full yield stage; the derivation of the prestress when the anchorage section passes through the double formation The ultimate bearing capacity of the anchor cable.

Description

technical field [0001] The invention relates to the field of geotechnical engineering, and mainly relates to a method for constructing a mechanical model of a prestressed anchor cable. Background technique [0002] Since the introduction of prestressed anchor cable technology in the 1960s, it has been widely used in the field of engineering construction in my country. Deep foundation pit support, structure anti-floating and anti-tilt, tension foundation of suspension cable buildings, etc. The force transmission mechanism of the prestressed anchor cable refers to the transmission and transfer law of the force in the anchoring medium when the prestressed anchor cable is subjected to tensile force in the rock and soil mass, mainly including the distribution of shear stress in the anchoring section and the final effect. The force transmission mechanism of the prestressed anchor cable can provide an important theoretical basis for the selection of the anchorage length and the det...

AI Technical Summary

Problems solved by technology

For example, Chinese patent document CN109117593A discloses a coupling analysis method of anchor cable prestress loss and rock mass creep, and the coupling analysis method of anchor cable prestress loss and rock mass creep is as follows: (1), build prestressed anchor cable reinforcement The mechanical model of the creeping rock mass test block is used to analyze the force of the anchor cable and the rock mass under the action of prestress; (2), considering the stable creep characteristics of the rock mass under low stress and the unsteady creep under high stress (3) Deduce the creep equation of the rock mass affected by the anchor cable prestress loss effect; (4) Get the calculation formula of the anchor cable prestress change with time (5), comparative analysis of the calculation results of theoretical formulas and the test results of existing documents; Chinese patent document CN108984957A discloses a calculation method for the effective anchorage length of non-prestressed anchor cables in rocky slopes, and first establishes non-prestressed anchors The rock mass failure model around the grouting body of the cable; the velocity field of the rock mass around the grouting body is established, the energy loss and external force power in the sliding plane are deduced, and the maximum pull-out force that the anchor cable can withstand is deduced according to the reciprocal theorem of internal and external work The calculation formula; establish the stress distribution of the calculation unit of the rock mass failure surface, and deduce the calculation formula of the maximum pull-out force that the anchor cable can bear according to the force balance condition; The calculation formula for the effective anchorage length of the anchor cable is obtained; however, the above theoretical model of the force transmission mechanism of the prestressed anchor cable is only applicable to the working condition where the anchorage section passes through a single formation

[0004] In actual engineering, when the soil layer of the foundation pit site is relatively complex, the anchorage section of the prestressed anchor cable will pass through a variety of strata. The optimized design will no longer be scientific and reasonable, and it is very likely to cause instability, damage or extravagance.

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