Abstract
The discontinuities of the rock mass pose a high impact on its response to the static load and make complexity in modeling in such area. Principal objective of this study is to analyze the stability and sensitivity of Golab transfer tunnel access (transfer water from Zayanderud River to Kashan). This tunnel with a length of 5.1 kilometers and inclination of 13.5 percent is located 120 kilometers from Isfahan city. Geologically, this zone is in the range of sediment structure of Sanandaj-Sirjan. The host rock mass consists of Limestone Mesozoic (Cretaceous). The general characteristics of the joints in the rock represent high distance, low persistence, low opening (2 - 3 mm), average roughness and low weathering. Given purpose of the project and the distinct element method is the most useful for modeling rock mass for static analysis. This paper examines the effect of parametric factors on the stability of tunnels via UDEC software, discrete element and empirical method. After modeling, instability of Golab tunnel by increasing the depth is identified and confirmed. RMR, Q and GSI as experimental procedure were employed to classify the rock mass, based on RMR classification. The route rock mass has been taken in I and II categories and based on the Q classification, the path rock masses are recognized acceptable.
Highlights
Till 1960s, planning and performing underground areas was based on experimental principles and the result was adjusted in the form of instructions and in 1970s, the result emerges in engineering classification
Distinct element methods (DEM) employ an explicit scheme to evolve the equations of motion of discrete bodies directly
This paper extends to determine the geological strength index (GSI) as well as using the distinct element method (UDEC software)
Summary
Till 1960s, planning and performing underground areas was based on experimental principles and the result was adjusted in the form of instructions and in 1970s, the result emerges in engineering classification. Along with the advancement of technology and existence of various software for the stability analysis of tunnels perform with more accurate and faster in a short time This issue doesn’t reject the use of other methods using experimental methods. Cundall developed a DEM code, Universal Distinct Element Code (UDEC) to model the blocky rock systems [1] [2]. Distinct element method (DEM) is one of the most appropriate methods for modeling of the rock mass static and dynamic analysis [3]. The Distinct Element method (DEM) can directly approximate the block structure of the jointed rock using arbitrary polyhedra. Applying this approach, pre-existing joints are readily incorporated into the DEM model. This paper extends to determine the geological strength index (GSI) as well as using the distinct element method (UDEC software)
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