STRAIN-DEGRADATION ANALYSIS OF TUNNEL STRUCTURES BASED ON TWIN-SHEAR UNIFIED STRENGTH CRITERION

Authors

  • YONGTAO BAI SCHOOL OF CIVIL ENGINEERING, CHONGQING UNIVERSITY, CHONGQING 400044, CHINA / INSTITUTE FOR RISK AND RELIABILITY, LEIBNIZ-UNIVERSITÄT HANNOVER, CALLINSTRAßE 34 30167 HANNOVER, GERMANY HTTPS://ORCID.ORG/0000-0002-0726-9593
  • SHAOYU GUAN DEPARTMENT OF CIVIL ENGINEERING, XI’AN JIAOTONG UNIVERSITY, XI’AN 710049, CHINA
  • ZHENYUN TANG THE KEY LABORATORY OF URBAN SECURITY AND DISASTER ENGINEERING OF MINISTRY OF EDUCATION, BEIJING UNIVERSITY OF TECHNOLOGY, BEIJING, CHINA
  • JULIO FLOREZ-LOPEZ UNIVERSIDADE FEDERAL DA INTEGRAÇÃO LATINO-AMERICANA - UNILA, FOZ DO IGUAÇU, PR, BRASIL

DOI:

https://doi.org/10.1590/1679-78255769

Abstract

THIS PAPER FOCUSES ON THE STABILITY BEHAVIOR OF TUNNEL STRUCTURES WITH A CIRCULAR HOLLOW SECTION BASED ON THE UNIFIED STRENGTH THEORY WITH A STRAIN-SOFTENING MODEL. A SIMPLIFIED NUMERICAL APPROACH IS PROPOSED FOR ANALYZING THE ELASTO-PLASTIC BEHAVIOR OF SURROUNDING ROCKS. A CONSTITUTIVE EQUATION IS PROPOSED BASED ON THE UNIFIED STRENGTH THEORY AND THE STRAIN-SOFTENING BEHAVIOR WAS TAKEN INTO ACCOUNT AS WELL WITH DEVIATORIC PLASTIC STRAIN CHOSEN AS THE SOFTENING PARAMETER. MEANWHILE, THE PLASTIC POTENTIAL FUNCTION CAN BE OBTAINED WITH THE ASSOCIATED FLOW RULE, BY WHICH THE SURROUNDING ROCKS CAN BE CLASSIFIED AS PLASTIC ZONE AND ELASTIC ZONE. THE SOLUTION IN PLASTIC ZONES ADOPTED THE DIFFERENTIAL METHOD SUBDIVIDING SURROUNDING ROCK INTO INFINITESIMAL CONCENTRIC ANNULI, IN WHICH THE RADIAL STRESSES DECREASE MONOTONICALLY WITH A DECREASE IN RADIAL COORDINATE. THE RELATIONSHIP OF THE INCREMENT OF STRESSES AND THE INCREMENT OF STRAINS IN ADJACENT ANNULI CAN BE DERIVED FROM EQUILIBRIUM, CONSTITUTIVE AND GEOMETRICAL EQUATIONS. THE NUMERICAL SOLUTION OF EACH ANNULUS IS CALCULATED FROM THE OUTMOST ANNULUS AT THE ELASTIC-PLASTIC INTERFACE. IN ADDITION, THE IMPACT OF THE INTERMEDIATE PRINCIPAL STRESS FACTOR AND THE CRITICAL SOFTENING PARAMETER ON THE SOLUTION, AND THE FACTORS OF INFLUENCE ON PLASTIC RADIUS ARE DISCUSSED.

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Published

2020-02-19 — Updated on 2020-02-19

Issue

Vol. 17 No. 2 (2020)

Section

Articles

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