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| The damage and failure mode of shaft structures crossing the geotechnical interface under the horizontal excitation of earthquake motion |
| ZAHNG Bu1,2, JI Ruoyu1, ZHONG Zilan1,2, XU Chengshun1,2, DU Xiuli1,2*
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1. Faculty of Architecture, Civil and Transportation Engineering, Beijing University of Technology, Beijing 100124, China;
2. Key Laboratory of Urban Security and Disaster Engineering of the Ministry of Education, Beijing University of Technology, Beijing 100124, China |
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Abstract Previous seismic damage of the underground shafts have shown that the structural safety of shaft are facing seriously threat under strong earthquakes and damage occurs near the rock soil interface. In actual engineering, the shaft inevitably crossed the geotechnical interface, and the seismic damage failure mechanism of the shaft structure at the site of the geotechnical interface had not yet been clarified. This research mainly studied the influence of the shaft lining strength and thickness parameters on the damage of the shaft under the horizontal earthquake motion. Based on the finite element software ABAQUS, a three-dimensional soil structure interaction model of shaft was established. The internal force distribution, diameter deformation rate, damage state and strain distribution of the shaft under the action of horizontal earthquake motion were studied by three-dimensional dynamic time history analysis method. The results showed that the axial force, shear force and bending moment of the shaft at the geotechnical interface were mutated, the axial thrust force was the tensile force at the geotechnical interface, while the hoop force was the pressure force. The damage position of the shaft was concentrated at the intersection of rock and soil and was manifested as tensile damage; The axial thrust force is the damage control force, and the axial tensile damage was aggravated as the strength and thickness of the shaft lining increased; The peak axial strain of the shaft was concentrated at the geotechnical interface; The axial strain of the shaft lining with a wall thickness of 0.6 m under C35 concrete strength was 1.3 times that under a wall thickness of 0.5 m.
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Received: 25 June 2023
Published: 20 September 2023
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