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Study On Mechanical Parameters Of Rock Mass Of Dam Foundation Of Yujianhe Reservoir In Guizhou Province

Posted on:2005-03-04Degree:MasterType:Thesis
Country:ChinaCandidate:H Q XuFull Text:PDF
GTID:2132360152970586Subject:Environmental Engineering
Abstract/Summary:PDF Full Text Request
Hydraulic engineering can artificially control the resources, environment and ecology system of the drainage area. With the development of economy, society and science and technology, the ability of enduring and resisting disasters is becoming much stronger, and the situation that people use water resources has effectively changed by dams.However, after dams have been constructed and operated, they also have become a kind of potential and huge threaten, and their security and service performance impact greatly the society and economy. The parameters estimation of rock mass in the study region is one of the hot topic in rock mass mechanics. Different mechanical parameters leads to different results, and improper mechanics parameters even incorrectly instructs to project design and construction. Many project design defaults derived from the deviation of the estimated parameters. The determination of mechanics parameters of rock mass is an important problem during the investigating, designing and constructing of projects because its rationality is the main determinant of the security and economy of the hydraulic engineering.For the important projects, the in-situ test is a direct method to determine the mechanics parameters of rock mass. Generally, it is very expensive and difficult to construct, and it is also affected by size effect. A large number of project experiences show that the internal relation exists between the small rock strength and the rock mass strength. So we always try to estimate the mechanical parameters of rock mass by analyzing the experimental data of mechanics parameters of rock samples and the geological data based on the field investigation, and acquire the parameters which are according with the practice by the contrast of multi-methods.Taken SongZiKan group and ShiZiShan group strata appeared in the dam foundation of YuJianHe reservoir in GuiZhou province for example, the structures characters and mechanics properties of rock mass were analyzed in this paper, and the methods of choosing the deformation and strength parameters of rock mass were discussed too. The rock is made up of the rock mass and the structural plane, so the rock mass structure and the mechanics properties of the structural plane are important factors of influencing the rock mechanics properties. So the structure characteristics and mechanics properties of structural plane are studied in detail in this paper. Based on the test results of the physical mechanics properties of the rock, the rock mechanical properties are analyzed, and the deformation parameters of rock masses were estimated by many methods including the fractal method and neural network method. Through comparison of the advantages and disadvantages of these methods, considering the engineering geology of the rock mass, the deformation parameters and strength parameters of rock masses can be selected comprehensively. Several study achievements have been obtained, which are described as follows:1. It is feasible to evaluate the rock mechanics properties and obtain the mechanical parameters of rock mass by analyzing the structure characteristics and mechanics properties of discontinuities, combining with experimental study of mechanical properties of rock.2. The characteristics of rock mass structures can be analyzed by statistical analysis of geometrical characteristics of discontinuities and Monte-Carlo simulation, which can also offer many important basis for estimating mechanical parameters of rock mass.3. The analysis of RQD can be realized through rock discontinuity network modeling and the credible result of rock mass quality evaluation can be obtained through proper classification methods.4 . For the fractured rock which has many discontinuities, Hoek-Brown experience formula is more proper to calculate the uniaxial compressive strength and uniaxial tensive strength comparing to other formulas and the result is more close to engineering facts.5. For methods used to evaluate mechanics parameters, we find that the values calculated by RMR method and Q m...
Keywords/Search Tags:rock mass of dam foundation, mechanics parameters of rock mass, SongZiKan group, ShiZiShan group, discontinuity, rock mass quality, Monte-Carlo simulation, fractal dimension, artificial neural network
PDF Full Text Request
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