scholarly journals In Situ Monitoring and Numerical Experiments on Vertical Deformation Profiles of Large-Scale Underground Caverns in Giant Hydropower Stations

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Hao Wu ◽  
Jian Liu ◽  
Xiaogang Wang ◽  
Lipeng Liu ◽  
Zhenhua Tian
Keyword(s):  
Large Scale ◽  
Surrounding Rock ◽  
In Situ Monitoring ◽  
Rock Deformation ◽  
Vertical Deformation ◽  
Spatial Response ◽  
Underground Caverns ◽  
Hydropower Stations ◽  
The Relationship

Spatial response is a feature of rock deformation in regions surrounding large-scale underground caverns and includes significant vertical components due to the construction method of layered excavation. This vertical response is different to the longitudinal response of excavation deformation surrounding shallow tunnels. The study of longitudinal deformation profiles (LDPs), which describe the spatial response of longitudinal tunnel excavation and surrounding rock deformation, is a mature field. However, there has been no independent discussion of the relationship between vertical excavation and the spatial response of deformation in large-scale underground caverns nor the incremental characteristics of layered excavation. In this paper, we define the attenuation function λ x of unloading strength based on theoretical analyses and numerical simulations. We also propose the concept and form of the vertical deformation profile (VDP) curve for the first time and apply it to the Baihetan and Lianghekou Hydropower Stations. After fitting the complete VDP curve with a Levenberg-Marquardt algorithm, we verify its validity by comparing predicted data with in situ monitoring data. The curve can be used to quantitatively analyze the relationship between layered excavation and incremental deformation of surrounding rock, providing a basis for the rapid evaluation of staged deformation during the excavation of large underground caverns. This study has practical significance for the control of deformation in rock surrounding excavations and decision-making during the construction progress.

Study on Deformation and Damage of Rock Mass Subject to High In Situ Stress by Using a Elastoplastic Damage Model and Considering the Impact of Weak Planes

2013 ◽  
Vol 838-841 ◽  
pp. 705-709
Author(s):  
Yun Hao Yang ◽  
Ren Kun Wang
Keyword(s):  
Rock Mass ◽  
Large Scale ◽  
Damage Model ◽  
Back Analysis ◽  
In Situ Stress ◽  
Surrounding Rock ◽  
High In Situ Stress ◽  
Underground Caverns ◽  
The Impact

Large scale underground caverns are under construction in high in-situ stress field at Houziyan hydropower station. To investigate deformation and damage of surrounding rock mass, a elastoplastic orthotropic damage model capable of describing induced orthotropic damage and post-peak behavior of hard rock is used, together with a effective approach accounting for the presence of weak planes. Then a displacement based back analysis was conducted by using the measured deformation data from extensometers. The computed displacements are in good agreement with the measured ones at most of measurement points, which confirm the validities of constitutive model and numerical simulation model. The result of simulation shows that damage of surrounding rock mass is mainly dominated by the high in-situ stress rather than the weak planes and heavy damage occur at the cavern shoulders and side walls.

Application of Long Anchor in Support Optimization of Soft Rock Tunnel

2013 ◽  
Vol 368-370 ◽  
pp. 1614-1624
Author(s):  
Yang Sun ◽  
Jian Ping Chen ◽  
Wei Zheng ◽  
Li Yu
Keyword(s):  
Soft Rock ◽  
Surrounding Rock ◽  
Parameters Optimization ◽  
In Situ Monitoring ◽  
Rock Deformation ◽  
New Thought ◽  
Supporting Structure ◽  
Rock Tunnel ◽  
Surrounding Rock Deformation

supporting structure parameters optimization is always a research focus in soft rock tunnel. Combined with Youfangping tunnel in Guzhu highway, the scheme of long anchor supporting has been provided. Usually the length of systematic anchor was determined according to experience, it often not reasonable. In order to determine the length of anchor, in-situ wave velocity test and theoretical calculation was used, and with the consideration of safety and economy, the length of anchor was determined as 4.5m finally; At the same time combined with in-situ monitoring measurement, two test sections was selected, and with the comparison of the designed supporting scheme and the original strong supporting scheme, it can be found that: no matter from the sight of surrounding rock deformation, stress applied on surrounding rock or force pattern of supporting structure, the supporting form by lengthening anchor can control surrounding rock deformation more effectively, can improve the bearing capacity of surrounding rock fully and improve the effect of supporting structure. And the supporting scheme of long anchor was more reasonable than the strong supporting scheme. This long anchor supporting scheme can provided new thought to supporting design of soft rock tunnel in Guzhu highway.

Judgement Method for Surrounding Rock Stability of Guanjiao Tunnel Based on Catastrophe Theory

2011 ◽  
Vol 90-93 ◽  
pp. 2307-2312 ◽  
Author(s):  
Wen Jiang Li ◽  
Su Min Zhang ◽  
Xian Min Han
Keyword(s):  
Plastic Strain ◽  
Catastrophe Theory ◽  
Soft Rock ◽  
Surrounding Rock ◽  
In Situ Monitoring ◽  
Engineering Practice ◽  
Stability Of Surrounding Rock ◽  
The Stability ◽  
Rock Tunnel

The stability judgement of surrounding rock is one of the key jobs in tunnel engineering. Taking the Erlongdong fault bundle section of Guanjiao Tunnel as the background, the stability of surrounding rock during construction of soft rock tunnel was discussed preliminarily. Based on plastic strain catastrophe theory, and combining numerical results and in-situ data, the limit displacements for stability of surrounding rock were analyzed and obtained corresponding to the in-situ monitoring technology. It shows that the limit displacements obtained corresponds to engineering practice primarily. The plastic strain catastrophe theory under unloading condition provides new thought for ground stability of deep soft rock tunnel and can be good guidance and valuable reference to construction decision making and deformation managing of similar tunnels.

Parabolic-Apex Numerical Back-Analysis of Mechanics Parameters of Surrounding Rock

2012 ◽  
Vol 204-208 ◽  
pp. 196-201 ◽  
Author(s):  
Jian Cong Xu ◽  
Yi Wei Xu
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Pressure Coefficient ◽  
Back Analysis ◽  
Surrounding Rock ◽  
In Situ Monitoring ◽  
Monitoring Data ◽  
3D Fem ◽  
Physical Mechanics

The parabolic-apex numerical back-analysis method (PNBM) was proposed to obtain such physical-mechanics parameters as Young's modulus and lateral pressure coefficient of surrounding rock by 3D FEM numerical analysis based on in-situ monitoring data. Taking Xiang-an Subsea Tunnel (located in Xiamen, Fujian Province, China) for example, adopting the PNBM using ABAQUS software, three dimensional elastic-plastic FEM-PNBM of tunnel surrounding rock was validated using in-situ monitoring data. The results show as follows: Using the PNBM, not only may high calculation precision be obtained, better meeting the demand of actual projects, but also more reasonable and reliable physical mechanics indices of surrounding rock such as Young's modulus and lateral confinement pressure coefficient, may be obtained. The applicability and the simplicity of this proposed method also support its usefulness.

3-D FLAC Numerical Analysis of Rheological Character and Stability of Underground Caverns Surrounding Rock Mass of Xiao Langdi Key Water Control Project

2006 ◽  
Vol 306-308 ◽  
pp. 1473-1478
Author(s):  
Wei Shen Zhu ◽  
Jian Hua Liu ◽  
Shu Cai Li
Keyword(s):  
Numerical Analysis ◽  
Back Analysis ◽  
Surrounding Rock ◽  
Construction Process ◽  
Water Control ◽  
Long Period ◽  
Underground Caverns ◽  
Rheological Character ◽  
Measured Displacement

A brief description is given to the visco-plastic constitutive model of 3-D FLAC software and some treating methods for the numerical analysis. The excavation steps and the exerting time of excavation loads are determined in the light of the real construction process. The rockmass mechanical parameters are determined according to back analysis of in-situ measured displacement data. The analysis results of displacement and stability of the opening complex surrounding rocks in the construction process and in a long period of time after excavation completion are given.

scholarly journals EFFECT OF BLASTING ON THE STABILITY OF LINING DURING EXCAVATION OF NEW TUNNEL NEAR THE EXISTING TUNNEL

2021 ◽  
Vol 30 (1) ◽  
Author(s):  
Tuan Minh Tran ◽  
Quang Huy Nguyen
Keyword(s):  
Field Data ◽  
Damage Zone ◽  
Field Tests ◽  
Surrounding Rock ◽  
In Situ Test ◽  
The Stability ◽  
Relationship Of ◽  
The Impact ◽  
The Relationship

In recent years, experimental and numerical researches on the effect of blasting pressure on the stability of existing tunnels was widely obtained. However, the effect of the blasting pressure during excavation a new tunnel or expansion old tunnels on an existing tunnel has disadvantages and still unclear. Some researches were carried out to study the relationship of the observed Peak Particle Velocity (PPV) on the lining areas along the existing tunnel direction, due to either the lack of in situ test data or the difficulty in conducting field tests, particularly for tunnels that are usually old and vulnerable after several decades of service. This paper introduces using numerical methods with the field data investigations on the effect of the blasting in a new tunnel on the surrounding rock mass and on the existing tunnel. The research results show that not only predicting the tunnel lining damage zone under the impact of blast loads but also determination peak maximum of explosion at the same time at the surface of tunnel working.

Quasi-distributed fiber-optic in-situ monitoring technology for large-scale measurement of soil water content and its application

2021 ◽  
Vol 294 ◽  
pp. 106373
Author(s):  
Meng-Ya Sun ◽  
Bin Shi ◽  
Cheng-Cheng Zhang ◽  
Xing Zheng ◽  
Jun-Yi Guo ◽  
...  
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Large Scale ◽  
Fiber Optic ◽  
In Situ Monitoring ◽  
Monitoring Technology

Analysis on Causes of Deformation and Failure of Large Scale Underground Powerhouse

2011 ◽  
Vol 71-78 ◽  
pp. 644-650 ◽  
Author(s):  
Jin Yu Dong ◽  
Ji Hong Yang ◽  
Guo Xiang Yang ◽  
Fa Quan Wu
Keyword(s):  
Large Scale ◽  
Shear Failure ◽  
Surrounding Rock ◽  
Concrete Cracking ◽  
Underground Powerhouse ◽  
Deformation And Failure ◽  
Underground Caverns ◽  
Geological Conditions ◽  
The Right

Jinoping No.1 is a dominant reservoir cascade hydropower station which locates at the downstream of Yalong river. The underground powerhouse locates at the right bank of the dam, lithology is marble that belongs to the second member of Zagunao group. It is constructed at region with very complicated geological conditions and high geo-stress. Concrete cracking, spalling and steel buckling and bending occurred at the downstream crown after supporting. This paper analysed the causes of deformation and failure through geological analysis and numerical simulation, and concluded that deformation and failure mainly occurred at the region where the quality of surrounding rock belongs to Ⅲ1 and had nothing to do with the unstable block cut by cracks; stress field of surrounding rock varied continueously with the proceeding of successive excavation of underground powerhouse, so the compressive stress and shear stress concentration occurred which caused the compression and shear failure of downstream crown and made it bending to the free face. It is significant to the further enforcement of this project and to the research on other similar underground caverns theoretically and practically.

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