Université de Liége THUY LOI UNIVERSITY & UNIVERSITY OF LIEGE FACULTY OF CIVIL ENGINEERING Presented by MAI THI NGAT ANALYZING THE CAUSES OF STRONG SEEPAGE ON XAHUONG DAM AND PROPOSING SOLUTIONS FOR HANDLING Major : Sustainable Hydraulic Structures StudentID# 148ULG09 MASTER THESIS Supervisor : Dr. HO SY TAM - Thuy Loi University Co-supervisor : Prof. RADU SARGHIUTA - University of Liege Ha Noi, 2016 MASTER THESIS SUSTAINABLE HYDRAULIC STRUTURES REASSURANCES NAME: MAI THI NGAT Major: Sustainable Hydraulic structure Student Number: 148ULG09 I hereby declare that I am the person who conducted this master thesis under the guidance of Dr. Ho Sy Tam and Prof.Radu Sarghiuta with the research topic in the thesis “Analyzing the causes of strong seepage on XaHuong dam and proposing the solution for handling”.
This is a new research topic which does not overlap with any dissertation before, so there is no copy of any public dissertation. The contents of the thesis are presented in accordance with regulations; the data resources and materials used in research are quoted sources. If there is any problem with the contents of this thesis, I would like to take full responsibility as prescribed. SIGN MAI THI NGAT MaiThiNgat Supervisor: Dr.
Ho Sy Tam Co-Supervisor: Prof Radu Sarghiuta MASTER THESIS SUSTAINABLE HYDRAULIC STRUTURES ACKNOWLEDGEMENTS Master Thesis in major of sustainable hydraulic structure “Analyzing the causes of strong seepage on XaHuong dam and proposing the solution for handling” was completed in August, 2016 In the process of implementation of the thesis, I always get the encouragement and devoted directions from my instructors _ Dr. Ho Sy Tam and Prof. I am really grateful for their invaluable help. I also would like to express our sincere thanks to all of my teachers in Sustainable Hydraulic structure Master course at Thuy Loi University, along with professors from University of Liege had imparted valuable specialized knowledge for me so that i can get this result.
Finally, I sincerely thank my family, my friends, and especially my classmates who had exchanged enthusiastically, contributed and encouraged me to complete this thesis. Sincerely SIGN MAI THI NGAT MaiThiNgat Supervisor: Dr. Ho Sy Tam Co-Supervisor: Prof Radu Sarghiuta MASTER THESIS SUSTAINABLE HYDRAULIC STRUTURES CATEGORY 1.1 THE URGENCY OF THE PROJIECT”.-- Án HT HT HH HH nHưệt 2 1.3 METHODOLOGY TO STUDY THE SUBJECTT.4 RESEARCH SCOPE OF THE STUDY. 5 <1 E311 ng rưkt 3 CHAPTER 1.1 INTRODUCTION OF THE PROJECTT”.1 Location of Project 4T©a.- - G c1 HH KH ng 4 1.2 Topographical and geomorphological Conditions.
ch HH HH 5 1.- - Q1 HH TH HH net 6 1.- - - c1 1n TH TH HH HH 10 1. Gv HH HH tt 10 1.2 Upstream dam slope .3 Downstream dam Slope .2 SEEPAGE PROBLEM TO XAHUONG DAM.3 STUDIES ON SEEPAGE INSTABILITY THROUGH EARTH DAM.1 Causes of permeability .-- -- --- 5 «kh ng ng nh 17 1.2 Basic principle of seepage ÍÏOW. HH TH ng HH ng 18 1. HH HT HH HH HH 19 1.6 Basic principle of seepage line 00.7 Permeable basic ©eQUAfIOII.8 Planar permeable eQU4tIOH.2 Calculation of perfect anISOfTODV.
G1111 HH ng rệt 26 MaiThiNgat Supervisor: Dr. Ho Sy Tam Co-Supervisor: Prof Radu Sarghiuta MASTER THESIS SUSTAINABLE HYDRAULIC STRUTURES 1.- on HH HT nh 26 1.2 Analysis about cause of permeablÏIty.- -- --c sss + ksk*ksnn se 30 CHAPTER 2: STUDY ABOUT CAUSES MAKING SEEPAGE INSTABILITY THROUGH THE BODY OF 2.1 INTRODUCTION ABOUT CALCULATION SOEFTWARE.2 Steps to CaÏCUÏA€. cọ HH HH tt 35 2.- HT ng HH ni ghh 40 2.1 Case 1: Normal working filter ÏAY€T.2 Case 2: Clogged filter layer 00. ee ee c1 kg ngư 44 2.
Case 3: Effects of anisotropic permeabÌIty.4 Case 4: Effect of Anisotropy 1n€TÏA€T. s55 + *svseeerereeresee 52 CHAPTER 3: SEEPAGE TREATMENT SOLUTIONS .1 Solution for case 3: Effect of anisotropic permeability .2 Solution for case 4: effect of anisotropic 1nferÌayT.2 ASSESSMENTS ABOUT RESULTS. Si 67 CHAPTER 4: CONCLUSION & RECOMMENDATION 68 MaiThiNgat Supervisor: Dr. Ho Sy Tam Co-Supervisor: Prof Radu Sarghiuta MASTER THESIS SUSTAINABLE HYDRAULIC STRUTURES LIST OF FIGURE Figure I- 1: Location of XaHuong reservoir ensembles .ccccccccccccccsccseccceeseceseeeseeessseeaes 4 Figure 1- 2: XAHUONG T€S€TVOÌI.
Ăn TH TT HH Hệ 7 Figure 1- 3: Upstream view of XaHuong @IH1. «s5 xxx skree 10 Figure 1- 4: Dam crest from the right ADUtMEN.ccccccccescceesseceeeseeeeseeeesneeeessesenee 10 Figure 1-5: Dam crest from the left ADULMENE. «key 10 Figure 1- 6: Crest of parapet WdlÏ. SG E981 11v vn tren Il Figure 1- 7: Foot of parapet Wl l.ccccccscccssccessccesscessecessecesseeeseceseeceeeceecesseeeseeseeeseaeeess Il Figure 1- 8: Dam Slope in the left ADUtMENE .cccccscccessceetccesseeeseeseseeseseseseesesenseennees 12 Figure 1- 9: Dam slope in the right aPUIIM©H.
sc vn hrkkkerrkvrrre 12 Figure 1- 10: Overall downstream dam SLOPE .eccccssccescccessceesecesseeenseceneeesaeeeaeeseaeeseaeenss 13 Figure I- 11: Dam slope m = 2.5, from elevation of +83.0m to dam cresf. 13 Figure I- 12: The first dam berm at elevation Of +83.cccccscccscccesscessecestetenseeeneeees 13 Figure I- 13: Dam slope m = 3.0 from elevation Of +71. 13 Figure 1- 14: Handling the seepage of dam slope from elevation +71. I5 Figure 1- 15: Concentrated rocks for seepage drainage ON sÏOD€.-s-«<<<5 T5 Figure T- 16: Seepage drainage on berm at elevation + 7Ï.
«cà cccc+sscssssses 16 Figure 1- 17: Cross-Section Of (ÍŒEH. G3181 899111 1k1 1 tk ngư 26 Figure I- 18: Transformation for Anisotropic CondifÏOTIS. «se c<cssssees 28 Figure I- 19: Effect of Anisotropy on Seepage through an Earth Dam. 29 Figure 2- 1: Geoslope Software interface .ĂĂ SG St vn rry 33 Figure 2- 2: Creating Analysis DFOD€TẨÏS.Ă- SG HH ng ngư 35 Figure 2- 3: Importing region from AutoCA DFOBTGIH.-- sccSccssssssessseeeeee 36 Figure 2- 4: Defining material ÏAY€TS.
cv tk tk tk kg key 36 Figure 2- 5:Defining hydraulic boundary COHHÏOPS.ccSẶSSSSS+ssekisseeerxses 37 Figure 2- 6: Drawing material ÏV€FES. cv vn kg rry 37 Figure 2- 7: Drawing boundary COHÌÏIÏOP-S.à cà SE hhhvnhrikkrrreereree 38 Figure 2- 8: SOWiNg dAta. SG n0 Hư 38 Figure 2- 9: Displaying T€SHÏHS.Ă TH TH HH Hư 39 MaiThiNgat Supervisor: Dr. Ho Sy Tam Co-Supervisor: Prof Radu Sarghiuta MASTER THESIS SUSTAINABLE HYDRAULIC STRUTURES Figure 2- 10 - VICWING T€]DOFÍ.
nh Figure 2- 11 : Drawing permeable grid and Sliding C€HẨ€F.ằ sec SSS<s+sv+ss2 Figure 2- 12 + Contributed material Ï(V€FS. «cv vớt Figure 2- 13 - Calculated diagram of seepage Stability for case Ï.-«‹ Figure 2- 14 - Seepage calculation results fOr CASC 1 .ccescccccscccccssccceesseetestseetstesetsasees Figure 2- 15 - Calculated result of slope slide stability (Normal load combination). Figure 2- 16 - Calculated diagram of seepage stability for CAS€ 2.-S- Figure 2- 17 - Seepage calculation results fOr CASC 2.eccecccscceseesetseeseeeseeenetseeeseeenees Figure 2- 18 - Calculated result of slope slide stability (Normal load combination). Figure 2- 19 - Calculated diagram of seepage stability for CAS Ÿ.««- Figure 2- 20 - Calculated diagram of slope stability (Normal load combination).
Figure 2- 2] - Seepage calculation results for CaS€ 3 (YdflO= 7) .««««cc<<s«+ Figure 2- 22 - Calculated result of slope slide stability (Normal load combination). Figure 2- 23 - Seepage calculation results for case 3(rafio= Ï0) .««<««- Figure 2- 24 - Calculated result of slope slide stability (Normal load combination). Figure 2- 25 - Seepage calculation results for case3(rafio= Ï4Í) .«««-«<«<«+ Figure 2- 26 - Calculated result of slope slide stability (Normal load combination). Figure 2- 27 - Seepage calculation results for CaS€3(TATIO=2O) .«-«-«-<<<«+ Figure 2- 2Š - Calculated result of slope slide stability (Normal load combination).
Figure 2- 29 - Contributed material layers .cccccccccccescccesscteessceeeneeeeesseesesseeeeeuseeensaaees Figure 2- 30 - Calculated diagram of seepage stability for Z=7Úm.« «+5 Figure 2- 31 - Seepage calculation results for Z= 70M .cccccccccccessecesseeeseeesseeeseeeenseeeas Figure 2- 32 - Calculated result of slope slide stability (Normal load combination). Figure 2- 33 - Calculated diagram for ZH.-- 5 kg nệt Figure 2- 34 - Seepage calculation results for ZŨIH. sec sssissiksekeee Figure 2- 35 - Calculated result of slope slide stability (Normal load combination). Figure 2- 36 - Calculated diagram for ZÔÍI.
ch he Figure 2- 37 - Seepage calculation results for ZŠ⁄ÍIH. cà skssikkesereesee Figure 2- 38 - Calculated result of slope slide stability (Normal load combination). MaiThiNgat Supervisor: Dr. Ho Sy Tam Co-Supervisor: Prof Radu Sarghiuta SUSTAINABLE HYDRAULIC STRUTURES Figure 3-2 Calculated diagram of seepage stability Figure 3- 3 Seepage calculation result.
Figure 3-4 Calculated diagram ofslople stability (Normat load combination) Figure 3-5: Calculated result ofslope slide stability (Normal load combination). Figure 3-6: Contributed material layers Figure 3-7: Calculated diagram of seepage stability Figure 3-8: Seepage calculation result Figure 3-9 Calculated diagram of slople stability (Normat load combination), Figure3- 10: Calculated result of slope slide stability (Normal load combination). MaiThiNgat ‘Supervisor: Dr. Ho Sy Tam.
Co-Supervisor: Prof Radu Sarghiuta LIST OF TABLE Table 2. 1: Mechanical and physical indicators of fill-soil for dam body and foundation 4 Table 2. 2: Ouput data of case 3 31 Table 2. 3: Output data of case 4 58 Table 3.
1: Ouput data 67 MaiThiNgat ‘Supervisor: Dr. Ho Sy Tam Co-Supervisor: Prof Radu Sarghiuta MASTER THESIS SUSTAINABLE HYDRAULIC STRUTURES PREMISE 1.1 THE URGENCY OF THE PROJECT Earth dam is a type of dam built by the existing soils in the building region such as clay, clayed , sandy loam, sand, gravel, cobbles .Earth dam has simple and stable structure, capable of highly mechanized during the construction and in most cases. Barth dam Widely applied in most countries. This type of dam has advantage of using local materials which are available at construction area, so it has cheaper construction costs comparing to other types of the same scale dams.
However, earth dam also contains many risks, easy to occur unsafe incident to dams if the designing Work and construction does not guarantee the requirements such as foundation treatment, dam structure selection, appropriate material planning for fill soil of an ‘embankment dam as well as densification ensure uniformity and tightness of each fill layer, According to statistic, permeability occupies high rate in the cause of making reservoir built with local materials unsafe. In our country, most of the earth dams are made of homogeneous soil. When water level rise and lowered erratically, it will destabilize the slope of dam, leading to sliding, subsidence, local erosion. Therefore, the calculation of stability mode for the earth dam is very important.
Usually we only calculate permeability in homogeneous environments. Concept of permeability of earth dài in case of homogeneous soil often do not lead to significant errors comparing to fact. If the dam body or the dam's waterproofing parts are constructed with materials relatively homogeneous with small value of heterogenous coefficient then we can solve the seepage problem with homogencous ‘environment. Moreover, beside case of normal calculation (isotropic environment), we must pay attention to the heterogeneity of the material (anisotropy of permeability).
The inhomogeneous - anisotropic usually occur because of earth dam construction MaiThiNgat T ‘Supervisor: Dr. Ho Sy Tam Co-Supervisor: Prof Radu Sarghiuta MASTER THESIS SUSTAINABLE HYDRAULIC STRUTURES technology with horizontal soil layers, having the difference in permeability coefficient between horizontal and vertical layers (kŠk”); whereas: kề, kỳ are permeability coefficients of horizontal x and vertical y In fact, we often see the type of land with permeable foundation, soil foundation and fill soil of dam includes many different layers. The problems of this type are complicated, because we have to mention the environment with multiple layers as well as complex boundary conditions. The seepage problem solutions that we ad learned only approximate and simple.
When calculating permeability, we must analyze the viability of the material with anisotropic permeability coefficient with different values (© take measures (© ‘overcome the adver: consequences of distortion repellent. Recently, there are 2 methods to calculate permeability: permeability calculation by analytical method (straight-line rate method of Lence - American ‘engineer, published in 1934) and by numerical model method (using software SEEP / `W version in 2007 by GEO-SLOPE International, Ltd, Development Canada). ‘Today, beside the the significant progress in using numerical methods in particular and the strong development of modem technology in general, we can solve the permeability problem more quickly and easily.