Engineering Properties Of Rock Mass Research Articles

Analysis of engineering properties of rock mass of Shah-wa-Arus dam site, Kabul, Afghanistan

The Shah-wa-Arus dam is currently being constructed on the Shakardara River, approximately 22 km to the north west of Kabul City, Afghanistan. The height and length of the dam are 77.5 m and 303 m, respectively, and the storage capacity of the dam is estimated around 9.38 million cubic meter. The type of the dam is roller-compacted concrete (RCC). It is a multi-purpose dam, designed to store water for irrigation, to mitigate flooding and generate electricity. The dam is located within a tectonically active zone, and the dam site has been strongly affected by tectonic activity. The paper presents results of comparison rock quality designation (RQD) and Lugeon parameters, based on a review and analysis of initial engineering-geological studies and additional field observations. The results of Lugeon and RQD were statistically evaluated in graphs and by using comparison of these graphs with all other conditions as of natural of this particular site. The obtained results show which state of the natural conditions is somehow a meaningful relationship between a Lugeon unit and RQD parameters. Finally, the rock mass of the dam foundation site is classified in accordance with the RMR classification.

Analysis of engineering properties of rock mass of Shah-wa-Arus dam site, Kabul, Afghanistan

Analysis of engineering properties of rock mass of Shah-wa-Arus dam site, Kabul, Afghanistan

Support design of underground openings in an asphaltite mine

A detailed study to design support systems for underground openings was carried out in this paper. Asphaltite, an energy source for thermal power plants, will be produced from the Uckardesler Asphaltite Vein in southwestern Turkey. This mine will be the first application of underground asphaltite production in the world. Two main geological formations, the Gercus formation and the Midyat formation, form the geological structure of the study area. The Gercus formation is conglomerate, sandstone, mudstone, clay, detritus, such as jibs, and the asphaltite vein located in the formation. The Midyat formation is mostly limestone. The cut and fill stoping method was selected for this mine in accordance with the geometry of the vein, topographic specifications, and expected annual production rates. Asphaltite will be excavated from the underground mine by continuous miners. The shapes and sizes of underground opening, which will include incline and ramp galleries, shafts, crosscut (X/C) galleries, main level galleries, and production galleries, were designed based on production method and rate. Rock mass classification systems and the finite element numerical method were applied to design support systems for the proposed underground openings. In this study, the engineering properties of rock masses were defined from field and laboratory studies for each formation and for asphaltite. Support systems for each underground opening were designed based on the suggestions of the rock mass rating (RMR) system and the Q system of rock mass classification. The suggested support systems were subjected to numerical analysis in order to evaluate their predicted performance. The results of the numerical modeling were analyzed to select the proper support system for each underground opening.

Research on the Spacing of Structural Plane Used in Rock Mass Structure Classification

Great achievements have been made in rock mass structure research to evaluate engineering properties of rock mass in the engineering geology field. In fact, rock mass structure can not only indicate the quantity of structural planes (discontinuities) and size of rock blocks, but also indicate the integrity and mechanical properties of the rock mass. More and more attention has been paid to rock mass quality classification by using rock mass structure. During the past 40 years, rock mass structure research has been carried out by many scholars, and various standards of rock mass structure classification have been proposed in different industries of different countries. In these standards, the most widely used index was the spacing of structural plane. However, it is a pity that the method of determining the spacing value is not unified in different standards, therefore, the structure type of a rock mass may be different according to different standard. But which kind of method to determine the spacing value is most reasonable It becomes an important problem to be solved. In this paper, rational method of determining the spacing of structural planes is demonstrated based on lots of statistical data in dam abutment rock mass of one large-scale hydroelectric project in Southwest China.

Research on the Spacing of Structural Plane Used in Rock Mass Structure Classification

Great achievements have been made in rock mass structure research to evaluate engineering properties of rock mass in the engineering geology field. In fact, rock mass structure can not only indicate the quantity of structural planes (discontinuities) and size of rock blocks, but also indicate the integrity and mechanical properties of the rock mass. More and more attention has been paid to rock mass quality classification by using rock mass structure. During the past 40 years, rock mass structure research has been carried out by many scholars, and various standards of rock mass structure classification have been proposed in different industries of different countries. In these standards, the most widely used index was the spacing of structural plane. However, it is a pity that the method of determining the spacing value is not unified in different standards, therefore, the structure type of a rock mass may be different according to different standard. But which kind of method to determine the spacing value is most reasonable? It becomes an important problem to be solved. In this paper, rational method of determining the spacing of structural planes is demonstrated based on lots of statistical data in dam abutment rock mass of one large-scale hydroelectric project in Southwest China.

Numerical Analyses of Seepage from Behesht Abad Dam Foundation

In this article, seepage phenomena through the karstic limestone foundation of Behesht Abad dam are investigated. In order to get a state of seepage and determine the depth of grouting curtain, it has been tried to evaluate the seepage of Behesht-Abad dam foundation and its abutments by the help of numerical analysis and UDEC 4.0 software. To perform this research, firstly, geological data during a study phase in Behesht Abad dam site was gathered, and then different methods have been used to calculate the engineering properties of rock mass. Therefore the structural model of dam foundation based on the geological data constructed and various boundary conditions including different heads were applied on the model and the suitable depth for the grouting curtain was proposed.

A method for fitting probability distributions to engineering properties of rock masses using Legendre orthogonal polynomials

A method is presented for fitting probability distributions of random variables describing the engineering properties of rock in this paper. The Legendre orthogonal polynomial (LPA method) with sample origin moments was used to approximate the PDF (probability density function) or CDF (cumulative distribution function) of rock random variable. It is distribution-free because no classical theoretical distributions are assumed in advance and the inference result provides a universal form of PDF. Six most commonly-used theoretical distributions were used to verify LPA method. Twenty groups’ random samples of traditional distribution by Monte Carlo method and four examples from observed data of mechanic parameters of rock were presented for illustrative purposes. The largest departure D n of Kolmogorov–Smirnov test and the RE (percentage relative error) of estimation by LPA method is smaller than that of PDF fitted by standard methods of statistical inference. The results show the PDF of rock variables can be accurately derived from LPA method with sample moments and the proposed method is suitable for approximating probability distributions of rock random variable.

Variability of the engineering properties of rock masses quantified by the geological strength index: the case of ophiolites with special emphasis on tunnelling

The paper presents a quantitative description, using the Geological Strength Index (GSI), of the rock masses within an ophiolitic complex including types with large variability due to their range of petrography, tectonic deformation and alteration. This description allows the estimation of the range of rock mass properties and the understanding of the dramatic changes in behaviour which can occur during tunnelling, from stable conditions to severe squeezing within the same formation at the same depth. The paper presents the geological model in which the ophiolitic complexes develop, their various petrographic types and their tectonic deformation, mainly due to overthrusts. The structure of the various rock masses includes all types from massive strong to sheared weak, while the conditions of discontinuities are in most cases fair to poor or very poor due to the fact that they are affected by serpentinisation and shearing. Serpentinisation also affects the initial intact rock itself, reducing its strength. Associated pillow lavas and tectonic melanges are also characterised. Based on the GSI, a classification of the behaviour in terms of tunnelling is presented, including stable conditions, structural instability, mild overstressing, stress dependant instability, squeezing and ravelling.