Seismic Response of a Water Transmission Pipeline Across a Fault Zone Adopting a Large-Scale Vibration Table Test

Longsheng Deng,Sen Ren,Yan Dai,Wen Fan,Pei Li,Wenzhong Zhang,Yubo Li

doi:10.3389/feart.2021.777551

Abstract

The seismic response is generally amplified significantly near the fault zone due to the influence of discontinuous interfaces and weak-broken geotechnical structures, which imposes a severe geologic hazard risk on the engineering crossing the fault. The Hanjiang to Weihe River Project (phase II) crosses many high seismic intensity regions and intersects with eight large-scale regional active faults. Seismic fortification of the pipelines across the fault zone is significant for the design and construction of the project. A large-scale vibration table test was adopted to investigate the seismic response and fault influences. The responses of accelerations, dynamic stresses, strains, and water pressures were obtained. The results show that the dynamic responses were amplified significantly by the fault zone and the hanging wall. The influence range of fault on acceleration response is approximately four times the fault width. The acceleration amplification ratio in the fault zone generally exceeds 1.35, even reaching 1.8, and the hanging wall amplification ratio is approximately 1.2. The dynamic soil pressure primarily depends on the acceleration distribution and is apparently influenced by pipeline location and model inhomogeneity. The pipeline is bent slightly along the axial direction, accompanied by expansion and shrinkage in the radial direction. The maximum tensile and compressive strains appear at the lower and upper pipeline boundaries near the middle section, respectively. Massive y-direction cracks developed in the soil, accompanied by slight seismic subsidence. The research findings could provide reasonable parameters for the seismic design and construction of the project.

Highlights

Faults are one of the most important geological settings in the Earth’s crust and are developed extensively in western China
This paper aims to investigate the seismic response of pipelines across the fault zone
The consideration of strata variation would cause an obvious complexity in the test design because a large number of sensors have to be arranged near the discontinuous interface to monitor the dynamic response

Summary

Introduction

Faults are one of the most important geological settings in the Earth’s crust and are developed extensively in western China. Fault activities generally induce various geological disasters, such as ground dislocations, landslides, collapses, and debris flows, posing a significant threat to people’s lives, properties and engineering constructions (Dhakal, 2021; Peng et al, 2021). As a lifeline project built either on the ground surface or buried in the soil, Pipeline Across Fault Seismic Response the pipeline cannot avoid crossing a fault belt in most conditions. Mitigation, and treatment of pipelines across faults is significant for the design and construction of projects. Scientists and engineers generally focus on the following aspects: 1) investigation of seismic damage of pipelines under strong earthquakes; 2) assessment of pipelines crossing the fault adopting analytical methods, numerical simulations, and physical modeling experiments; and 3) mitigation and prevention of pipelines crossing the fault belt

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Discussion

Conclusion