The Effect of Alluvial Foundation on the Earth Dams Settlement
- 1 Department of Mining Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
- 2 Department of Mining Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
- 3 Faculty of Water and Environmental Engineering, Shahid Beheshti University, Tehran, Iran
- 4 Faculty of Mining Engineering, Tarbiat Modares University, Tehran, Iran
Abstract
Careful monitoring in the earth dams, to measure deformation caused by settlement and movement has always been a concern for engineers in the field. In order to measure settlement and deformation of earth dams, usually the precision instruments of settlement set and combined Inclinometer that is commonly referred to IS instrument, will be used. In some dams, because the thickness of alluvium is high and there is no possibility of alluvium removal (technically and economically and in terms of performance), there is no possibility to place the end of IS instrument (precision instruments of Inclinometer-settlement set) in the rock foundation. Inevitably, have to accept installing pipes in the weak and the deformable alluvial foundation that this leads to errors in the calculation of the actual settlement (absolute settlement) in different parts of the dam body. The purpose of this paper is to present new and refine criteria for predicting settlement and deformation in earth dams. The study is based on conditions in three dams with a deformation quite alluvial (Agh Chai, Narmashir and Gilan-e Gharb) to provide settlement criteria affected by alluvial foundation. To achieve this goal, the settlement of dams was simulated by using finite difference method with FLAC3D software and then the modeling results were compared with reading IS instrument. In the end, the caliber of the model and validate the results, by using regression analysis techniques and scrutinized modeling parameters with real situations and then by using MATLAB software and Curve Fitting Toolbox, a new criteria for the settlement based on elasticity modulus, cohesion, friction angle, density of earth dam and alluvial foundation was obtained. The results of these studies show that, by using the new criteria measures, the amount of settlement and deformation for the dams with alluvial foundation can be corrected after instrument readings and the error rate in reading IS instrument can be greatly reduced.
- Bell, F.G. (1995) Engineering Treatment of Dam. F.N. Spon, Durban.
- Ahangari, K., Moeinossadat, S.R., Behnia, D., Behnia, M. and Moeinossadat, S.H. (2012) Application of New Methods for Intelligent ANN, ANFIS and GEP for Predicting the Static Elasticity Modulus of Limerock. International Conference on Nonlinear Modeling & Optimization, Shomal University, Amol, 28-29 August 2012.
- Chrzanowski, A., Chen, Y.Q. and Secord, J. (2007) Geometrical Analysis of Deformation Surveys. Proceedings (MIT), Deformation Measurements Workshop, MIT, Boston, 31 October-1 November 2007, 170-206.
- Chrzanowski, A., Chen, Y.Q. and Secord, J. (2008). On the Strain Analysis of Tectonic Movements Using Fault Crossing Geodetic Surveys. Tectonophysics, 97, 297-315.
- Chugh, A.K. and Falvey, H.T. (1978) A Computer Program for Planar Seepage Analysis in a Zoned Anisotropic Medium by the Boundary Element Method. Advances in Engineering Software, 5, 196-201.
- Duncan, J.M. (1997) State of the Art: Static Stability and Deformation Analysis. In: Seed, R.B. and Boulanger, R.W., Eds., Proceedings Specialty Conference on Stability and Performance of Slopes and Embankments II, ASCE, 222-266.
- Duncan, J.M. (1996) State of the Art: Limit Equilibrium and Finite-Element Analysis of Slopes, ASCE. Journal of Geotechnical Engineering, 122, 577-595.
- Marandi, M., Vaezinejad, M. and Khavari, E. (2012) Prediction Of Concrete Faced Rock Fill Dams Settlements Using Genetic Programming Algorithm. International Journal of Geoscience, 3, 601-609.
- Curve Fitting Toolbox—MATLAB. The Math Works Inc., Natick, Massachusetts.
- Final Technical Report, Second Phase Studies of AQCHAY Earth Dam (2003) Tehran, Consulting Engineering MAHAB QODS, Repot No. 19, 50-442.
- Final Technical Report, Second Phase Studies of Narmashir Earth Dam (2000) Tehran, Consulting Engineering MAHAB QODS, Repot No. 3, 720-2840.
- Final Technical Report, Second Phase Studies of GILANQARB Earth Dam (2001) Tehran, Consulting Engineering AB NIROU, Repot No. 3, 230-460.
- Itasca Consulting Group, Inc. (2004) FLAC3D User Manual: Version 5.0. USA.