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Study on Crack Development of Concrete Lining with Insufficient Lining Thickness Based on CZM Method
Jian Liu1, Xuesen Zhang1, Gaohang Lv2
1School of Qilu Transportation, Shandong University, 12550 East Second Ring Road, Jinan 250002, China.
Materials (Basel, Switzerland)
|December 24, 2021
Summary
Insufficient tunnel lining thickness is a primary cause of concrete lining cracks. This study used the Cohesive Zone Model (CZM) to analyze crack propagation and structural failure, revealing significant impacts on tunnel safety.
Area of Science:
- Civil Engineering
- Materials Science
- Structural Mechanics
Background:
- Tunnel concrete lining cracking is a common operational defect.
- Insufficient lining thickness is a key factor contributing to this cracking.
- Understanding crack behavior is crucial for tunnel structural integrity.
Purpose of the Study:
- To investigate the cracking behavior of concrete specimens and tunnel structures due to insufficient lining thickness.
- To analyze crack propagation mechanisms and characteristics under varying lining thicknesses.
- To quantitatively assess the development rules of lining cracks.
Main Methods:
- Utilized the Cohesive Zone Model (CZM) with zero-thickness cohesive elements.
- Developed standard concrete specimen models and a 3D numerical tunnel model.
- Compared crack development across different concrete grades and simulated various lining thicknesses.
Main Results:
- The CZM effectively simulated concrete fracture behavior.
- Higher concrete strength grades correlated with increased cohesive damage and crack area.
- Insufficient lining thickness altered stress distribution, reduced safety, and promoted cracking.
- The impact of insufficient thickness was more pronounced when not fully in contact with surrounding rock.
Conclusions:
- The Cohesive Zone Model is a reliable tool for simulating concrete fracture in tunnels.
- Lining thickness is a critical parameter influencing tunnel structural safety and crack development.
- Further research into optimizing lining thickness can enhance tunnel operational lifespan and safety.
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