Structure Force Analysis for Concrete Single Curved Arch Dam of Shuangchong Reservoir

Abstract

Arch dam is a beautiful engineering structure, it has good mechanical properties, it is widely used in water conservancy engineering, in order to have a clear understanding for mechanical characteristics of arch dam structure. Using the finite element method for concrete arch dam of shuangchong reservoir gives simulation analysis,and the arch stress, deformation distribution in the course of construction and operation.The results show that a reasonable for concrete arch structure of shuangchong reservoir to meet the design requirements.Research for the design and construction of concrete single curved arch structures provide some reference. The results showed that, concrete single curved arch dam of Shuangchong reservoir is reasonable and feasible, arch dam’s maximum tensile stress value appear junction of arch dam and bedrock, most of the stress values are smaller, stress and displacement values can meet engineering requirements. Keywords-Shuangchong reservoir; Single curved arch; Force analysis; Stress distribution; Finite element method. I. ENGINEERING SITUATION Shuangchong Reservoir is located in Mian River tributary of Liuyang County, Hunan Province, which is a reservoir to generate electricity, combined with irrigation water resources and hydropower engineering. It works by dams, two dams, power plants and other buildings. Dams normal water level is 60.80m.Maximum height is 13.6m.Check flood dam is 12.6m.Design water level is 11.6m and dead water level is 9.8m.Tail level is 2.2m. Dam is a narrow V-shaped valleys, single concrete arch dam, dam thicker than 0.15. II. ARCH CALCULATION MODEL A Model Parameters The concrete arch dam of Shuangchong reservoir uses the concrete strength class C15,elastic modulus 22 1  E GPa, poisson's ratio 167 . 0 1   [1-2]. Bulk density 24 1   kN/m .Dam valley sides hillside slope approximation1:1,dam good geological conditions, exposed bedrock, fresh, intact hard rock for Banxi group sandy slate and quartz sandstone.Rock elastic modulus 18 2  E GPa, Poisson's ratio 28 . 0 2   . B Model Element Concrete arch dam and bedrock structure model uses 8-node isoparametric block element. The element is applied to three-dimensional model entity structure,has plasticity,creep,swelling,stress stiffening,large deformation and large strain properties,the element has eight nodes and each node has three translational degrees of freedom[3-5] . C Model Size The size of the entire calculation model is down the river to fetch 65m,perpendicular to the direction of the river to take 55m,vertical take 33.6m,simulation range model is 65m × 55m × 33.6m[6-7].Arch and rock element division shown in Fig .1. Figure 1. Arch and bedrock FEM division International Conference on Mechatronics, Electronic, Industrial and Control Engineering (MEIC 2014) © 2014. The authors Published by Atlantis Press 1179 D Calculation Condition Considering the arch structure during operation of the mechanical characteristics[8-9],the main consideration of the following three kinds of calculation condition is that case1(dead water level and weight),case2(design water level and tail water level and weight),case3(check flood level and tail water level and weight). III. ARCH STRUCTURE ANALYSIS A Stress Analysis Through the stress analysis for the concrete arch dam of shuangchong reservoir, calculated the various conditions of arch dam sectional crown stress on key points, the stress calculation results shown in Table 1. TABLE I. EACH CONDITION OF ARCH DAM SECTIONAL CROWN STRESS ON KEY POINTS(MPA) Location 1 2 3 4 5 6 7 8 Case 1 Upstream face Circumferential stress -0.01 -0.12 -0.14 -0.26 -0.23 -0.14 -0.07 -0.04 Longitudinal stress -0.04 -0.08 -0.07 -0.26 -0.24 -0.12 -0.04 -0.05 Downstrea m face Circumferential stress -0.01 0.12 0.05 0.10 0.04 -0.01 -0.02 -0.03 Longitudinal stress -0.24 -0.11 -0.15 0.03 0.05 -0.02 -0.04 -0.07 Case 2 Upstream face Circumferential stress -0.01 -0.15 -0.17 -0.40 -0.43 -0.34 -0.22 -0.14 Longitudinal stress 0.01 -0.03 0.03 -0.26 -0.35 -0.24 -0.08 -0.05 Downstrea m face Circumferential stress -0.01 0.15 0.08 0.19 0.11 0.03 -0.01 0.01 Longitudinal stress -0.28 -0.15 -0.23 0.04 0.16 0.10 -0.01 -0.01 Case 3 Upstream face Circumferential stress -0.01 -0.18 -0.20 -0.57 -0.69 -0.65 -0.54 -0.44 Longitudinal stress 0.08 0.04 0.16 -0.20 -0.40 -0.35 -0.16 -0.01 Downstrea m face Circumferential stress -0.01 0.19 0.12 0.30 0.19 0.04 -0.04 -0.06 Longitudinal stress -0.31 -0.19 -0.32 0.02 0.23 0.21 0.08 -0.01 As can be seen from Table 1, the three conditions,the stress on the upstream face and the downstream face Arch relatively low,does not exceed the tensile strength of concrete C15,the design value of the compressive strength,to meet the strength requirements. To more clearly in the operating conditions arch overall stress distribution, Fig .2 through Fig .5 shows the main arch under stress case 2,the circumferential stress and vertical stress contour map.