Isolation Mechanism and Method for Buried Segmental Pipeline under Earhquake-Induced Large Displacement

2011 ◽  
Vol 99-100 ◽  
pp. 410-413
Author(s):  
Ai Ping Tang ◽  
Ai Hua Wen ◽  
Li Hua Gai ◽  
Ru Hong Zhong
Keyword(s):  
Slope Failure ◽  
Soil Types ◽  
Response Analysis ◽  
Buried Pipeline ◽  
Soil Slope ◽  
Seismic Response Analysis ◽  
Ground Displacement ◽  
Isolation System ◽  
Reliable Isolation ◽  
Rock And Soil

This paper deals with an isolation design methods of buried segment pipeline for large ground displacement in earthquake. The buried pipeline is always damaged due to the strong shaking and earthquake-induced large or permant ground displacement and deformation (PGD), including liquefaction, rock and soil slope failure, fault and fissure. Based on the seismic response analysis for buried segment pipeline, the isolation mechanism and an equipment for resisting ground displacement trigged by liquefaction and fault is presented in this paper. Some related parameters to isolation system like stiffness and damp of isolator, soil types and its displacement, depth of pipeline, are discussed for developing a reliable isolation system fitting the buried segment pipeline.

Research and Development of Three-Dimensional Isolation System for Sodium-Cooled Fast Reactor: Part 1 — Proposal of Analytical Models Based on Loading Tests

2018 ◽  
Author(s):  
Tsuyoshi Fukasawa ◽  
Shigeki Okamura ◽  
Takahiro Somaki ◽  
Takayuki Miyagawa ◽  
Masato Uchita ◽  
...  
Keyword(s):  
Seismic Response ◽  
Analytical Model ◽  
Three Dimensional ◽  
Analytical Models ◽  
Response Analysis ◽  
Seismic Response Analysis ◽  
Natural Period ◽  
Isolation System ◽  
Loading Tests ◽  
Rubber Bearings

This paper describes that the analytical model for the three-dimensional isolation system [1], which consists of thick rubber bearings, disc springs and oil dampers, is created through loading tests. The new-type analytical models of each element are proposed to improve the prediction accuracy of the seismic response analysis. The concept of the three-dimensional isolation system has been proposed to ensure the structural integrity for large reactor vessels. The primary specifications of the three-dimensional isolation system are a horizontal natural period of 3.4 s and a vertical natural period of 0.33 s. The investigations of horizontal isolation performances have been conducted for the various types of isolation devices, beginning with rubber bearings, whereas the previous studies focused on the vertical isolation performances are only a few. Hence, isolation characteristics, such as restoring force and damping force, should be clarified by loading tests using vertical seismic isolation elements, and analytical model to assess the seismic response should be identified on the basis of the loading test results. This paper presents a new analytical model with providing of the differential equations to improve the prediction accuracy and demonstrates the seismic performance, including beyond-design-basis ground motion, for the three-dimensional isolation system by the seismic response analysis.

Research on the Mechanism of Progressive Slope Evolution and its Failure Criterion

2013 ◽  
Vol 864-867 ◽  
pp. 765-770 ◽  
Author(s):  
Wei Shui Fei ◽  
Cong Ling Zhang ◽  
Zhi Qiang Wu
Keyword(s):  
Stress State ◽  
Failure Criterion ◽  
Slope Failure ◽  
Failure Process ◽  
Soil Slope ◽  
Unstable Failure ◽  
Total Failure ◽  
Slice Method ◽  
Rock And Soil ◽  
Sliding Zone

The unstable failure of rock and soil slope was a progressive evolution process from local failure to total failure. The no-uniformity of rock and soil materials and differences of boundary conditions caused the discrepancy of stress field, together with the elastic-plastic characteristics of the sliding zone which controls the progressive unstable failure process. In this paper, any point of slop sliding zone was taken for the research object. On basis of limit slice method, the mechanical condition of slice was considered as a plane strain problem. According to Mohr-Coulomb linear failure criterion the stress state of a point is obtained with selecting stress function to establish the mechanical criterion of progressive slope failure. The analysis of engineering example shows that the mechanical criterion is reasonable to estimate the state of progressive slope evolution.

Infrasound signal characteristics of rock soil landslide and experience with its engineering application

2020 ◽  
Author(s):  
Xiang Fu ◽  
Yuxin Ban ◽  
Qiang Xie ◽  
Chunbo He
Keyword(s):  
Slope Failure ◽  
Peak Frequency ◽  
Soil Mass ◽  
Landslide Monitoring ◽  
Soil Slope ◽  
Displacement Signal ◽  
Signal Characteristics ◽  
Mechanical Signal ◽  
Infrasound Signal ◽  
Rock And Soil

<p>As the infrasound signal has the advantages of slow energy attenuation, strong ability to cross obstacles and no need of contact acquisition, it is of great significance to take advantage of the infrasound signal in the process of deformation and failure of rock and soil mass to realize remote rapid monitoring and early warning of geological disasters. The infrasound signal characteristics of soil slope failure and rock under different stress states (compression, shear and tension) were compared by indoor and outdoor tests. The results showed that there was an obvious waveform of infrasound signal at the site of soil slope damage. The infrasound signal appeared mainly in elastic and plastic deformation stages under the compression state, the peak frequency of the infrasound signal was about 7 Hz. The concentration of signal power was slightly less than that under the compression state, and the peak frequency was about 8 Hz. The infrasound signal always associated with the whole loading process under tension state, and there were two bands of frequency center, in which the lower frequency was close to that of the compression test specimen, and the higher frequency was 3 Hz larger. On this basis, using the infrasound characteristics of rock and soil mass failure, the infrasound and other monitoring methods were carried out for Xinpu landslide in Fengjie, Chongqing, China. After the occurrence of the landslide, the infrasound signal characteristics of rock and soil failure were basically the same as those of indoor tests. The low-frequency signals were mainly monitored. At the same time, the monitoring results showed that the peak value of the infrasound signal reached before the mechanical signal, and the mechanical signal was monitored prior to the displacement signal. The infrasound signal can be 3-5 hours ahead of displacement signal. This regularity has important scientific and application value for landslide monitoring and prediction.</p>

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