Optimizing Method of Main Caverns in Large Underground Water-Sealed Storage Caverns

2021 ◽  
Author(s):  
Yang An ◽  
E-chuan Yan ◽  
Xing-ming Li ◽  
Shao-ping Huang
Keyword(s):  
Rock Mass ◽  
Large Scale ◽  
Distinct Element ◽  
Strength Criterion ◽  
Axial Direction ◽  
Optimization Method ◽  
Underground Water ◽  
Land Resource ◽  
Maximum Displacement ◽  
Distinct Element Code

Abstract As a main method of petroleum strategic reserve in China, underground water-sealed storage cavern owns lots of outstanding advantages, such as low operating costs, high safety, and land resource conservation. Main caverns are important structure in underground project and the layout parameters and excavation scheme will have significant impact on overall project quality. The optimization method of main cavern layout and excavation scheme was put forward by a proposed large-scale underground water-sealed cavern project in China. First, based on field survey results, the Hoek-Brown strength criterion combined with rock mass quality Q classification system was used to estimate the equivalent mechanical parameters of rock mass. Second, the numerical experiments were carried out by relying on 3 Dimensions Distinct Element Code (3DEC). The discontinuous medium model was adopted, and displacements of key points, maximum displacement values and volume of the plastic zone were used as evaluation indicators. Axial direction, buried depth, spacing and excavation scheme of main caverns have been optimized. Results showed that axial direction should adopt NW325°, buried depth of cavern roof should locate at -100m, and distance between adjacent main caverns should be 1.5 times the span (36m). The “jump excavation” mode was recommended in construction. That is, the caverns on both sides should be excavated first, and the middle cavern should be excavated later. This mode could effectively reduce the interaction effect between caverns. This method has the characteristics of easy data acquisition and strong operability. It could be used to guide design and construction of similar projects . As a main method of petroleum strategic reserve in China, underground water-sealed storage cavern owns lots of outstanding advantages, such as low operating costs, high safety, and land resource conservation. Main caverns are important structure in underground project and the layout parameters and excavation scheme will have significant impact on overall project quality. The optimization method of main cavern layout and excavation scheme was put forward by a proposed large-scale underground water-sealed cavern project in China. First, based on field survey results, the Hoek-Brown strength criterion combined with rock mass quality Q classification system was used to estimate the equivalent mechanical parameters of rock mass. Second, the numerical experiments were carried out by relying on 3 Dimensions Distinct Element Code (3DEC). The discontinuous medium model was adopted, and displacements of key points, maximum displacement values and volume of the plastic zone were used as evaluation indicators. Axial direction, buried depth, spacing and excavation scheme of main caverns have been optimized. Results showed that axial direction should adopt NW325°, buried depth of cavern roof should locate at -100m, and distance between adjacent main caverns should be 1.5 times the span (36m). The “jump excavation” mode was recommended in construction. That is, the caverns on both sides should be excavated first, and the middle cavern should be excavated later. This mode could effectively reduce the interaction effect between caverns. This method has the characteristics of easy data acquisition and strong operability. It could be used to guide design and construction of similar projects .

Research on Back Analysis of Parameters for Excavation of the Underground Cavern Group of a Large-Scale Hydro-Power Station by Using Orthogonal Optimization

2012 ◽  
Vol 170-173 ◽  
pp. 3356-3360
Author(s):  
Wen Dong Yang ◽  
Xi Chao Gao ◽  
Yan Mei Zhang ◽  
Jia Yang ◽  
Gang Wang ◽  
...  
Keyword(s):  
Rock Mass ◽  
Large Scale ◽  
Back Analysis ◽  
Element Model ◽  
Optimization Method ◽  
Orthogonal Experimental Design ◽  
Grey System ◽  
Power Station ◽  
Hydro Power ◽  
Underground Cavern

Engineering rock mass is a highly complex grey system, it is impossible to get all the parameters of rock mass by theoretical methods or field measurement approach. Underground engineering feedback analysis method is a reliable way to improve the design, optimization and construction. Based on the field data of underground cavern of a large-scale hydro-power station, the three-dimensional finite element model is established, and orthogonal experimental design and multi-objective optimization method are used for the rapid back analysis. This method could be used for obtaining the rock parameters by inversion calculating in the underground cavern construction of a large-scale hydro-power station. Meanwhile, the inversion parameters could also be applied in the excavation simulation for the next phase and the rock deformation and stability is predicted afterwards. The design and construction sectors are supposed to get its feedback in time, which effectively guarantees the stability of the surrounding rocks.

Study on Seepage Field of Artificial Water Curtains for Underground Petroleum Storage Caverns in Fractured Rock Mass

2013 ◽  
Vol 353-356 ◽  
pp. 1666-1670
Author(s):  
Yun Peng Zhang ◽  
Song Yu ◽  
Wei Shen Zhu
Keyword(s):  
Rock Mass ◽  
Fractured Rock ◽  
Distinct Element ◽  
Water Pressure ◽  
Underground Water ◽  
Calculation Model ◽  
Fractured Rock Mass ◽  
Water Curtain ◽  
Underground Caverns ◽  
Water Seal

Based on joint statistics from the in-situ survey, using numerical simulation technique of joint network (Monte-Carlo method), the calculation model of fractured rock mass is generated. Underground seepage discharge filed in fractured rock mass surrounding storage caverns is analyzed by using distinct element method. The result of simulation has shown good agreement with surveying data. Two cases have been simulated that is water curtains is installed and is not installed. Water pressure distributions in joints are investigated in these two cases. It is shown that in the case without water curtain the groundwater in joints which locate the upper of underground caverns is drained out and water sealed conditions is completely unrealized. When water curtain pressure is set at 0.3MPa, can underground water seal the storage caverns.

Research on Multiple Holes Grouting of Fractured Rock Mass

2012 ◽  
Vol 256-259 ◽  
pp. 547-551 ◽  
Author(s):  
Yong Xu ◽  
Wei Hong Peng
Keyword(s):  
Rock Mass ◽  
Fractured Rock ◽  
Distinct Element ◽  
Fracture Aperture ◽  
Diffusion Distance ◽  
Fractured Rock Mass ◽  
Grouting Pressure ◽  
Universal Distinct Element Code ◽  
Distinct Element Code ◽  
Multiple Holes

Considering the seepage stress coupling of fractured rock mass, the multiple holes grouting problems were simulated to analyse the spread regularity by Universal Distinct Element Code(UDEC).The results show that the correlation between grouting pressure and the diffusion distance is positive, whereas the correlation between ground stress and diffusion distance is negative; With the raising of grouting holes, the diffusion distance is increasing and becoming more uniform in all directions, and the grout pressure and saturation is falling and attenuation amplitude is decreasing along the direction of grout diffusion; With the increasing of fracture aperture, the grout diffusion distance is increasing, and the grout pressure and saturation attenuation amplitude is decreasing along the direction of grout diffusion.

scholarly journals Numerical Analyses on Deformation and Failure Characteristics of Surrounding Rock of Gob-Side Entry Retention by Roof Cutting

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Qunying Wu ◽  
Binhui Liu ◽  
Jun Yang ◽  
Yajun Wang ◽  
Kuikui Chen ◽  
...  
Keyword(s):  
Large Scale ◽  
Distinct Element ◽  
Simulation Software ◽  
Surrounding Rock ◽  
Failure Characteristics ◽  
Deformation And Failure ◽  
Temporary Support ◽  
Universal Distinct Element Code ◽  
Distinct Element Code ◽  
Borehole Televiewer

Universal distinct element code (UDEC) is a simulation software based on the discrete element method, widely used in geotechnical mining. However, in the UDEC, when simulating large-scale excavation, the subsidence of the fractured zone is almost equal to the mining height, which makes the deformation value calculated in the study of gob-side entry retention too large. To solve this problem, in this paper, the double-yield constitutive model is applied to the whole caving zone to analyze the deformation and failure characteristics of surrounding rock along gob-side entry retaining by roof cutting. The results of the simulation are in good agreement with the result of drilling peeking (drilling observation by borehole televiewer) and field condition (observation and measurement in the field). Finally, by using this numerical method, the effects of roadway width, temporary support, and coal side support on the failure of the roof and the arc coal side are studied.

Stability Analysis of Cut Rock Slope with Reinforcement by Steel Cables

2007 ◽  
Vol 353-358 ◽  
pp. 2509-2512
Author(s):  
Shui Lin Wang ◽  
Ying Hui Lu ◽  
Yu Yong Jiao ◽  
Chun Guang Li
Keyword(s):  
Rock Mass ◽  
Rock Slope ◽  
Slip Surface ◽  
Distinct Element ◽  
Jointed Rock ◽  
Structural Formation ◽  
Bedding Planes ◽  
Strength Reduction Technique ◽  
Before And After ◽  
Distinct Element Code

There are a large number of cracks, joints and layers with different scales and orientations in the rock masses. With the structural formation in it, the rock mass is unlike the isotropic and homogenous materials in physics and mechanics characteristics, and the failure of the rock mass is controlled by those discontinuities. This paper studies the stability of a jointed rock slope with bedding-planes. Universal Distinct Element Code (UDEC) is used to carry out the numerical analysis. The factor of safety (FOS) and failure mode are obtained by strength reduction technique before and after the steel bolts are installed in the slope. In addition, the forces along the bolts indicate that they reaches the maximum value in the potential slip surface of the slope.

Large-scale brittle and ductile toppling of rock slopes

2002 ◽  
Vol 39 (4) ◽  
pp. 773-788 ◽  
Author(s):  
Susan L Nichol ◽  
Oldrich Hungr ◽  
S G Evans
Keyword(s):  
Rock Mass ◽  
Parametric Study ◽  
Large Scale ◽  
Distinct Element ◽  
Rock Avalanche ◽  
Granitic Rocks ◽  
Failure Behaviour ◽  
First Case ◽  
Discontinuity Orientation ◽  
Flexural Toppling

Slow, ductile toppling of rock masses commonly creates large-scale mountain slope deformations. In some cases, rock toppling can initiate an extremely rapid catastrophic landslide. This theoretical and field-based study was aimed at distinguishing the two alternative modes of toppling. The idea that certain key parameters of the undeformed rock mass may influence failure behaviour in a quantifiable way was examined through a parametric study of a large rock slope using the universal distinct element code (UDEC). The slope was modelled using variations of rock mass strength, discontinuity orientation and persistence, and toe over-steepening. The results indicated two distinct types of failure behaviour: (i) ductile, self-stabilizing flexural toppling in weak rock with a single dominant joint set; and (ii) brittle, catastrophic block toppling in strong rock containing persistent, down-slope oriented or horizontal cross-joints, which act as surfaces of separation at the base of the toppling blocks. The two mechanisms exhibit very different patterns of prefailure stress. During flexural toppling, the major principal stress is oriented predominantly parallel with the slope surface. In the case of block toppling, it is vertical and a large part of the unstable volume is horizontally destressed. Boundaries between the two types of behaviour have been approximately mapped. Two field case studies were then examined in light of the results. The first case involves a block topple in strong granitic rocks that failed catastrophically and produced a high velocity rock avalanche; and the second case is a large flexural topple in metamorphic rocks, exhibiting slow deformations.Key words: rock toppling, landslide, distinct element model, parametric study, hazard assessment.

scholarly journals A brief analysis of behaviour possibility of a jointed rock mass near to longwall excavation face simulation using Distinct Elements Method (DEM) in the context of the Beam on Elastic Foundation (BEF) theory

2019 ◽  
Vol 106 ◽  
pp. 01015
Author(s):  
Krzysztof Tomiczek
Keyword(s):  
Rock Mass ◽  
Elastic Foundation ◽  
Distinct Element ◽  
Beam Theory ◽  
Wave Theory ◽  
Jointed Rock ◽  
Coal Bed ◽  
Face Advance ◽  
Rock Masses ◽  
Distinct Element Code

Rock masses are discontinuous medium. Using the program based on the Distinct Element Method (DEM) UDEC (Universal Distinct Element Code) a 2D model of the rock mass near the longwall face was built. The UDEC code, due to its properties, is particularly suitable for modelling discontinuous and jointed rock masses. The coal bed lying at a depth of 700m had a thickness of 3m and was mined by longwall system with caving. The total face advance was 415m. The model had dimensions of 1500×500m (w×h). A vertical stress of σz=7.2MPa was applied to the upper edge of the model. The mechanized support protected the roof for a length of 4m at a distance of 2m from the face of the longwall. During simulation, among others, vertical displacements of roof and vertical stresses were closely examined. There were observed phenomena of bending, cracking, loosening and falling of roof blocks of rock. The results of numerical simulations were compared with the results of analytical solutions. The calculations were based on the solutions of the elastic foundation beam theory and the stress wave theory. Comparable shapes of arch pressure σzmax and the range of its impact were obtained.

scholarly journals 2D numerical analysis of the seismic response of a karst rock mass: importance of underground caves and geostructural details

2020 ◽  
Vol 42 (1) ◽  
pp. 61-73
Author(s):  
Bruno Giovanni ◽  
Carucci Fabrizio
Keyword(s):  
Rock Mass ◽  
Seismic Response ◽  
Distinct Element ◽  
Seismic Energy ◽  
Karst Cave ◽  
Karst Caves ◽  
Local Seismic Response ◽  
Distinct Element Code ◽  
Static Conditions

AbstractThe present study shows the results of a 2D local seismic response (LSR) analysis, simulated for a geomechanical model consisting of a layered carbonate rock mass with hypogean karst caves and a structural–lithostratigraphic complex setting, in an area within the Municipality of Turi (Apulia, Italy). In this case study a Distinct Element Code (DEM) code (UDEC) was used for the LSR simulations conducted on a model both in the absence and in the presence of two overlapping karst caves. The preliminary stress–strain model analysis show some tensile yielding points clustered on the roof of the upper karst cave, already in static conditions, and the phenomenon becomes even more noticeable in dynamic conditions. This is perfectly in agreement with the real occurrence of a sinkhole that brought to the light the underlying karst cave, in the case study area, in the recent past.The amplification/deamplification factor (FA) was calculated as the ratio of the top value to the bottom value in the model, both of the max X-acceleration and of the spectral Fourier amplitude in three different ranges of frequencies, in order to estimate the effects of LSR on the X-component of the seismic input. According to the previous studies, the results obtained show a generalised deamplification of the seismic ground motion at the top of the model, both without and with underground karst caves, caused by the presence of the upper karst cave and by the seismic energy absorption because of layers’ discontinuity.

In Situ Tests on Creep Behavior of Rock Mass with Joint or Shearing Zone in Foundation of Large-Scale Hydroelectric Projects

2004 ◽  
Vol 261-263 ◽  
pp. 1097-1102 ◽  
Author(s):  
Jian Liu ◽  
Xia Ting Feng ◽  
Xiu Li Ding ◽  
Huo Ming Zhou
Keyword(s):  
Rock Mass ◽  
Creep Behavior ◽  
Large Scale ◽  
Time Dependent ◽  
Three Gorges Project ◽  
Three Gorges ◽  
The Three Gorges ◽  
The Three Gorges Project

The time-dependent behavior of rock mass, which is generally governed by joints and shearing zones, is of great significance for engineering design and prediction of long-term deformation and stability. In situ creep test is a more effective method than laboratory test in characterizing the creep behavior of rock mass with joint or shearing zone due to the complexity of field conditions. A series of in situ creep tests on granite with joint at the shiplock area of the Three-Gorges Project and basalt with shearing zone at the right abutment of the Xiluodu Project were performed in this study. Based on the test results, the stress-displacement-time responses of the joints and basalt are analyzed, and their time-dependent constitutive model and model coefficients are given, which is crucial for the design to prevent the creep deformations of rock masses from causing the failure of the operation of the shiplock gate at the Three-Gorges Project and long-term stability of the Xiluodu arc dam.

Sign in / Sign up

Export Citation Format

Share Document