Slope modelling applied for slope movement at kalibawang irrigation channel, KM 15 9 yogyakarta, indonesia

SLOPE MODELLING APPLIED FOR SLOPE MOVEMENT AT KALIBAWANG IRRIGATION CHANNEL, KM15.9 YOGYAKARTA, INDONESIA by : Nguyen Dinh Tu 04/1535/PS The Graduate School Gadjah Mada University Yogyakarta July, 2007 SLOPE MODELLING APPLIED FOR SLOPE MOVEMENT AT KALIBAWANG IRRIGATION CHANNEL, KM15.9 YOGYAKARTA, INDONESIA Dissertation Submitted to Gadjah Mada University to obtain the Degree of Doctor in Geological Engineering at Gadjah Mada University Defended against the objections of the Dissertation Examination committee, The Graduate School Gadjah Mada University on 23th, July, 2007 by Nguyen Dinh Tu 04/1535/PS Born Thanh Hoa - Vietnam STATEMENTS Hereby, I declare that there is no result or duplication in this dissertation that has been proposed to obtain an academic degree from university There is no result or idea that has been reported or published by other authors except those cited in this dissertation and written in the reference Yogyakarta, July, 2007 Nguyen Dinh Tu Acknowledgments First of all, I would like to deeply thank my Mom, a virtuous Mom who has managed to bring her son up all the way to his PhD She has devoted all her life to her children Mom, you and Papa have instilled the love of learning in me by telling me the disadvantages that an illiterate has to face up to in his life Since Papa died, you have alone brought all your children up, alone managed to overcome the hardships Mom, you are my idol and I love you so much This thesis is for you Second, my gratitude and appreciation is specified to my Promotor, Prof Kabul Basah Suryolelono, Department of Civil Engineering and Environmental, Faculty of Engineering, Gadjah Mada University, for his enthusiasm, fortitude, and precious guidance in detail during my research at UGM Thanks to CoPromotor, Prof Kenji Aoki, Department of Urban and Environmental Engineering, Faculty of Engineering, Kyoto University, Kyoto, Japan who strongly encouraged me to finish my research I consider you as a father who has given an affection and perseverance for his son I would like to give a special thanks to Assoc Prof Dr Heru Hendrayana, Co- Promotor, Department of Geological Engineering, Faculty of Engineering, UGM; and Dr Hary Christady Hardiyatmo, Co- Promotor, Department of Civil Engineering and Environmental, Faculty of Engineering, UGM; Assoc Prof Dr Subagyo Pramumijoyo, Department of Geological Engineering, Faculty of Engineering, UGM, for their lots of invaluable guidance not only in this research but suggestions on other social things during my staying in Yogyakarta i A special-big thanks goes to Assoc Prof Dr Dwikorita Karnawati, CoPromotor, Head of Department of Geological Engineering, Faculty of Engineering, Gadjah Mada University, for her encouragement and her infinite guidance throughout this research work I deeply appreciate for her care in everything throughout this research I would like to show my deep appreciation to all my lecturers at UGM, for their attention to give valuable discussion on related subjects I would like to give a special thanks to Assoc Prof Dr Yoshitada Mito, Department of Urban and Environmental Engineering, Faculty of Engineering, Kyoto University, Kyoto, Japan for his intensive guidance and priceless suggestion during my research Thanks to Mr Chang Chuan Sheng, doctor student, Mr Susumu Kurokawa, master student, and all students of Department of Urban and Environmental Engineering, Faculty of Engineering, Kyoto University, for their intensive guidance and expert help during my staying in Kyoto I have to say special thanks to Assoc Prof Dr Nguyen Viet Ky and Assoc Prof Dr Le Phuoc Hao, Dr Phan Thi San Ha, Dr Nguyen Manh Thuy, Dr Dau Van Ngo, Ms Hoang Thi Hong Hanh, Geology and Petroleum Faculty, Ho Chi Minh City University of Technology, Vietnam for their intensive leading and kind help to study at Gadjah Mada University and Kyoto University A deep thanks goes to Mr Dany and Mr.Sito, my very good collaborators, for their useful help during monitoring time Thanks to Ms.Angeline Abrenica, AUN-SEED/Net master student, Department of Geological Engineering, UGM, for her kind helps to during writing this thesis Thanks for her checking and ii correcting on my writing Thanks are also due to Dissertation Examination Committee for their comments and suggestions I would like to show my sincere thanks to all my teachers since my younger age up to now for their guidance to upgrade my knowledge to the right way Other special thanks go to all AUN/SEED-Net scholar friends regardless of their background, nationality, religion and political belief I gratefully acknowledge to JICA and AUN/SEED-Net for providing me financial support for attending International Conferences and throughout my study of Doctoral Degree Thanks to Gadjah Mada University and Geological Engineering Department as well as Kyoto University and Department of Urban and Environmental Engineering, for their cooperation as host institution Meanwhile, thanks also go to Ho Chi Minh City University of Technology and Geotechnics Department, where I studied Bachelor and Master degree as well as where I have been working from 2001 to now Last but not least, I would like to deeply thank my family, my brother Mr Nguyen Xuan Thuy and all my closed friends, who strongly encouraged me to overcome the hardships during this research I am indebted to all of you iii ABSTRACT Kalibawang Irrigation Channel has been found to be threatened by landslide risk in every rainy season Among many types of slope movement ever found, slope creeping is the most devastating hazard to the infrastructures and the private properties In the case of slope at Km 15.9 which is located in Mejing village of Kulon Progo Regency, Yogyakarta Special Province, the continuously slow slope movement is suspected to induce additional stress on the bridge and the channel bridge downhill to deform in every rainy season To help solve that problem, this research is conducted, under the AUN/SEED-Net program supported by JICA, to understand the mechanism of creeping as well as to choose the most appropriative modeling applied for slope movement prediction with special consideration given to the local climate and geology Field investigation, laboratory testing, and field performance monitoring are utilized to investigate the site characteristics and to monitor the spatial and temporal slope behaviors Numerical analysis, consisting of modeling of slope hydrological process and slope stability analysis, (the Distinct Element Methods of Particle Flow Code 2D, the limit equilibrium methods of GeoSlope/W) are used to enhance or add to the engineering judgment on that process Results show that the movement of colluvial slope is very complex It has been found that some movements have occurred not only at the contact between the colluvial deposit and the base of mudstone, but also at the zone above ground water table The movements at the contact between colluvial deposit and mudstone may have been induced by pore-water pressure in response to the fluctuations in ground water level (increasing or losing pore-water pressure) or perhaps caused by the capillary rise or suction loss in response to the wetting of soil by rain infiltration Meanwhile, creeping occurred dominantly at the contact between the mudstone layer and tuffaceous medium sandstone as well as tuffaceous fine sandstone, although the tuffaceous fine sandstone had a high SPT value It has been observed that the slope movement depends on both rainfall and the stage of rainfall Moreover, all of the recorded movements are noticed to be not only relatively parallel to the slope dip direction but also followed different trends It has also been noted that the groundwater table achieved its maximum level with the same value as the accumulated rain days (275-285mm) and rain days (300-310mm) Hence, these values can be used to infer the time when the GWT level is at its maximum and the movement will be most intense Meanwhile, the results of PFC model are in close agreement with the monitoring results Therefore, it can be said that the PFC model is the appropriate model which could be applied for slope movement of this area as well as of other areas with the same condition Keywords: slope movement, creeping zone, colluvial deposits, strain-gauges, stress, rainfall, PFC model iv TABLE OF CONTENTS Page ACKNOWLEDGEMENTS ABSTRACT TABLE OF CONTENTS LIST OF TABLES LIST OF FIGURES ACRONYMS AND SYMBOLS CHAPTER i iv v viii x xvii INTRODUCTION 1.1 Formulation of the Problem 1.2 Authenticity of the Research 1.3 Objectives of the Research 1.4 Expected Benefits of the Research 1.5 Scope of Research Work CHAPTER LITERATURE REVIEWS 10 2.1 Definition and Classification of Landslides 10 2.2 Landslide in Colluvial Soil 15 2.3 2.2.1 Definition of creep 15 2.2.2 Definition of colluvium 17 2.2.3 Slope instability in colluvium 17 2.2.4 Description and mechanics of colluvial landslide processes 19 2.2.5 Characteristics of colluvium affecting slope stability 23 2.2.6 Effect of geomorphic factors 26 2.2.7 Hydrological effect 27 2.2.8 Effect of Fire 29 Movement of water 31 2.3.1 Saturation runoff 31 2.3.2 Infiltration 32 v 2.3.3 Water flow in saturated zone 37 2.4 Water affect soil properties 40 2.5 Hydrological landslide-triggering thresholds 48 2.5.1 Direct correlation between Rainfall and Landslide 50 2.5.2 Statistical rainfall-triggering thresholds 51 2.5.3 Ground water level trigger shallow mass movement 54 2.5.4 Identification of hydrological triggering mechanisms 57 2.5.5 Deterministic rainfall triggering thresholds Shallow soil slips 59 2.5.6 Landslides at the soil-bedrock contact 63 2.6 Analysis and Modeling of Slope Hydrology 66 2.7 The Theory of Limit Equilibrium in GeoSlope/W Model 72 2.8 The Contact Constitutive Model in Particle Flow Code 80 2.9 Hypotheses 91 CHAPTER METHOD OF RESEARCH 92 3.1 Desk Study and Literature Review 92 3.2 Research Instruments 93 3.3 3.4 3.2.1 Field Apparatus 93 3.2.2 Laboratory Work 93 Research Procedure 94 3.3.1 Initial site investigation 94 3.3.2 Field Instrumentation and Field Performance Monitoring 94 3.3.3 Monitoring Program 96 3.3.3.1 Installation of Piezometers 97 3.3.3.2 Installation of extensometers 99 3.3.3.3 Installation of strain gauges 101 Simulation modelling and Slope stability analysis 104 CHAPTER RESULT AND DISCUSSION 106 vi 5.h The PFC Model In this research, the balls in PFC model were assumed are soil particles and they are having the properties of soil particles (the micro properties for each layer are calibrated prior to the simulation by using biaxial test The association between the PFC synthetic material and a particular physical material is established by the simulated material testing) Thus, the balls which were presented the mudstone-sandstone particles in basement layer (mudstonesandstone layer) could be move by laws using in PFC model The basic input parameters The soil density and five micro parameters are used for the contact model in Particle Flow Code 2D (PFC2D) Ec (the Young’s modulus at each particle-particle contact) kn/ks ( the ratio of particle normal to shear stiffness) μ (the particle friction coefficient that applies when the contact bond has broken) σc (mean and std dev., normal strength) τc (mean and std dev., shear strength) Their values for each layer are shown in Table 17 Table 17 The micro-parameters used in PFC model No Material Particle Density (kg/m3) Young’s modulus EC (N/m2) The ratio of particles normal to shear stiffness kn/ks Particle friction Coefficient μ(Ф) Tuff sandy clay 2760 7.18E+07 10 0.10 2690 4.00E+07 10 0.24 2720 9.14E+08 11 0.54 2580 5.00E+07 10 0.60 2720 8.12E+07 12 0.20 2640 9.18E+07 12 0.41 Tufaceous clay Tufaceous mudstone-claystone breccia (2nd period) Tufaceous mudstone-claystone andesitic breccia Tuff Tufaceous mudstone-claystone breccia (1st period) Tufaceous claystone breccia 2620 9.0E+07 11 0.30 Sandy clay 2630 9.2E+07 13 0.61 Mudstone-Sandstone 2750 9.2E+07 13 0.54 35 PFC2D Model result Setting the model First, 7.000 balls with distribution radius of 0.52-0.86 m are created randomly within the rectangular geometry surrounded by four walls (the rectangular size is 228.13 m x 400 m), and then dropped by gravity After reaching a steady state condition, the logical balls are chosen to build the model (base on the coordinate of ball) The final model consists of 3.530 balls which are set in layers base on the cross section (Figure 32 and 33) The input parameters of each layer are shown in Table 17 Figure 32: Total 7.000 balls with distribution radius of 0.52-0.86m after reaching a steady state condition Figure 33: The model consists 3.530 balls are set in layers For fluid flow simulation, 2.300 cells are created in the model (Figure 34) The continuity and Navier-Stokes (N-S) equations were solved numerically in Euclidian Cartesian coordinates which derives the pressure and velocity vector for each fixed grid (cell) by considering the existence of balls within the cell The driving forces from fluid flow are applied to balls as body forces In this formulation, both fluid-phase and solid-phase contribute to the pressure gradient of the system 36 As mentioned in the hypothesis section, because this slope is a part of small hill with the highest point at SG-1 (the top of the hill), the water resource of this slope is only rainfall on its area A B Figure 34: The model is applied with 2.300 fluid cells before fluid flow simulation In this simulation, the fluid velocity was considered in relation to the velocity of raindrops; the maximum rainfall in the research area, touch to the ground and the infiltration rate of the layers The infiltration rate reflects from the result of field permeability of the layers and the final fluid velocity was determined from the trials Base on the monitoring result, the ground water flows in all layers from A to B Thus, it requests the difference of pressure between boundary Y_up (upper boundary) and Y_lo (below boundary) as well as the difference of pressure between boundary X_up (left boundary) and X_lo (right boundary) The boundary condition is set as slip wall, fluid velocity parallel to wall surface is non-zero at the wall surface, to the sidewalls and a pressure boundary is specified for the X_up,Y_up: 4x10e5 Pa and the X_lo, Y_lo : 0.0 Pa The fluid velocity is 1e-6 m/s, the density and viscosity of water are 1000kg/m3 and 1.0x10-3 Pa.s Their values are shown in Table 16 Table 18 The parameters used in fluid flow simulation Water X_up (0, 0; 0,40) Pressure 4.105 Pa Boundary X_lo (230, 0; 230,40) Pressure Pa 2300 Y_up (0, 40; 230,40) Pressure 4.105 Pa cells Y_lo (0, 0; 230,0) Pressure Pa Density 1000 kg/m3 Viscosity 1.0x 10-3 Pa.s Velocity 1.0x10-6 m/s 37 Simulation and discussion The simulation is stopped when the maximum (or average) unbalanced force is smaller compared to the maximum (or average) contact force in the model of packed particles According to the 10-5 ratio is set, the simulation stopped at step 12.262 in case without water flow (the first case) During this simulation, the maximum unbalanced force fluctuated from 40-80kN in the first 5.000 steps and decreased gradually from step 5.000 to end Meanwhile the average unbalanced force reached maximum at step 1.000 and decreased gradually, (Table 19 and Figure 35) Table 19 The average unbalanced and maximum unbalanced force in first 10.000 steps in case without water flow ( force unit: kN) a b Figure 35: The average unbalanced force (a) and maximum unbalanced force (b) in first 10.000 steps in case without water flow 38 Figure 36: Figure 37: The motion (a) and contact force (b) at the beginning in case without water flow The motion (a) and contact force (b) after 10.000 steps in case without water flow At the beginning of simulation, nearly no tension is found (Figure 36) The tension occurs at the first steps and more clearly after 2.000 steps and 5.000 steps From step 5.000 to the end, the tension occurs dominantly at the surface of mudstone layer around SG-2, SG-3 and occurs strongly from Pz-2 to the toe of slope, (Figure 37) In the second case of fluid flow simulation, the result revealed that the differences between two cases are not only on the unbalanced force value and distribution of force chains (compression and tension) but also on the creeping zone This simulation shows a difference of unbalanced force from the first steps, the maximum unbalanced force achieves 533 kN at step 1.000 and 39 decreases gradually from this step to step 80.000 After that, it increases gradually and achieves 400 kN at step 202.000 and keeps this constant (400 kN) during simulation days (non stop) Meanwhile the simulation in case without water flow stops at step 12.262, (Table 20, Figure 38 and Figure 39) Table 20 The average unbalanced and maximum unbalanced force in first 10.000 steps in case with water flow ( force unit: kN) a b Figure 38: The average unbalanced force (a) and maximum unbalanced force (b) in first 10.000 steps in case with water flow a Stop at step 12.262 Non Stop b Stop at step 12.262 Figure 39: Non Stop Comparing average unbalanced force (a) and maximum unbalanced force (b) between two cases with and without water flow 40 The distribution of force chains (compression and tension) between two cases are different, while the tension occurs dominantly at the surface of mudstone layer around SG-2, SG-3 and occurs strongly from Pz-2 to the toe of slope in case without water flow, the tension occurs almost slope profile in case with water flow In addition, the distributed density of compression in the second case is less than the distributed density of compression in the first case, (Figure 37 and 40) Figure 40: The simulation after 10.000 steps (in case with water flow) Although having the limitation in presentation exactly the very thin layers or the especial soil like plastic soil of this slope as well as the behaviour of soil when conversion the soil properties to parameters, the PFC simulation result are still in agreement with the monitoring result (about the location and density of displacement of movements) The tension in simulation result can be accepted with 15-20% of error when comparing with the strain-gauge monitoring result, (Figure 41) 41 Depths of movement Figure 41: Comparing the PFC simulation result with monitoring result Conclusion Although the time for rain monitoring was just July 2005 to Jun 2006, however, the complete graph of rain characteristics of the area was made based on the result of Kalibawang station, the final result agrees to the fluctuation of GWT The groundwater table achieved its maximum level with the same value as the accumulated rain days (275-285mm) and rain days (300-310mm) These values can be used to infer the time when the GWT level is at its maximum and the movement will be most intense By using this rain gauge, especially during the rainy season, we would be able to tell when the GWT is greatly affected by the rain If the rainfall get over 1800mm in three continuous months, then the groundwater table would be affected strongly In this time, GWT will increase formidably and will reach its maximum level in some boreholes Being aware of GWT fluctuation is crucial analyzing the creeping of this slope The monitoring result revealed that some movements have occurred not only at the contact between colluvial deposit and base of mudstone, but also at the zone above ground water table The movements at the contact between colluvial deposit and mudstone may have been induced by pore-water pressure in response 42 to the fluctuations in ground water level or perhaps caused by the capillary rise or suction loss in response to the wetting of soil by rain infiltration The creeping occurred dominantly at the contact between the mudstone layer and tuffaceous medium sandstone as well as tuffaceous fine sandstone, although the tuffaceous fine sandstone had a high SPT value (Table 10) Rapid increase of ground water table (1-2m/day) is due to the rapid increase in pore-water pressure which likewise result to rapid decrease in shear strength In Pz-2, the pore-water pressure reached up to ~90kPa in mid-end March and first-and April 2006 This was especially considered during the analysis of the effect of pore-water pressure to creeping at SG-3 and SG-4 The monitoring result also relieved that all GWTs achieved their maximum value at the same time Particularly for the GWTs of borehole located on the top of the slope which achieved their maximum value in the mid-April At depths where ground water table fluctuated in a long time, as in the depths of 11.5m (SG-2) and 6.5m (SG-3), the groundwater table strongly affected the creeping The strain value increased rapidly in the time GWT achieved this depth and more rapidly when GWT decreased from this depth to the deeper levels (Figure 16 and 17) This result revealed that not only the change of soil properties and increase of pore-water pressure but also the lost of pore-water pressure affected the movement The monitoring result also showed that the slope movements were complex and that they did not depend only on rain intensity but also on rain stage The movements also occurred in different directions The movements in SG-3 and SG-4 are considered to be the main forces which caused the deformation of the channel and bridge The average strain values are relatively similar in the first five months (Jan 05 to May 05) and became quite different in the next months Especially in the last three months, some movements had very big strain values (more than 5.000 x 10-6 strain) The strain values of shallower movements were noted to be higher than the strain values of deeper movements 43 Some new ideas were invented during the analysis of the monitoring result Two of them are very important in analyzing slope stability The first was the correlation of slope movement and slope hydrology as well as drilling log The second was the synthetic force method mentioned above This invention was used to find the real direction of movement This is not only useful for understanding mechanism of slope movement but also useful for deciding a solution to protect the slope For Extensometers, all noticeable changes in readings had close relation to rainfall (after 2days), so that every apparent change in the reading from the five Extensometers coincides on the same date The result of the monitoring showed that slope movement of colluvial soil is very complex It seems that the daily movement distances that were measured at some extensometers were the result of shrinking and swelling processes or may be due to the movement at the end and starting points of the extensometers Having a detailed measurement is very much necessary in order to set a basic landmark, as well as to set a geodesic system for all points of extensometers if ever such method is going to be employed in future colluvial soil monitoring studies Some information shown in Table could be use to explain the mechanism of movement at the top of slope as well as the deformation of the school The EX-5 get the maximum value +62mm on September 30, 2006, stand by for days and decreased in the days after For the modeling, despite the differences of unbalanced force value, distribution of force chains (compression and tension), the results of PFC2D in two cases (with and without water flow) are in agreement with the monitoring result The zone which caused the deformation of the channel and the bridge is around Pz-2 to the toe of slope The most unstable zone of the GeoSlope/W model could be concluded as the zone which caused the deformation of the channel and the bridge while the creeping zone map in PFC model could be applied for slope movement Applying fluid flow in PFC model makes the movement in rainy season become clear 44 Under the circumstances of time limitation and research condition, the chosen PFC model is the most appropriate model which could be applied for slope movement of this area as well as in other areas with the same condition Recommendation The lack of sufficient experience and unfamiliarity with the use of Extensometer in monitoring the movement of colluvial soil, made it difficult for the exact behavior of slope movement to be established Having a detailed measurement is very much necessary in order to set a basic landmark, as well as to set a geodesic system for all points of Extensometers if ever such method is going to be employed in future colluvial soil monitoring studies For the strain-gauge monitoring, transferring (or converting) the strain value to displacement value or setting several inclinometers is very significant to better understand the complete mechanism of colluvial soil creeping For Geoslope/W model, more soil samples are recommended for testing in order to find the relationship between the strength parameters and water content Information on the influence of water on strength parameter will give the relative function of rainfall-water content-strength parameters These parameters are found to be the most important factors to consider in It analyzing slope stability of colluvial soil creeping The PFC2D modeling used in this study is probably the new PFC2D approach applied to colluvial soil creeping in Indonesia It is important, however, that some modifications be made to make the model as similar as possible to the conditions in the study area (Example: The modification like setting the balls in sandstone-mudstone so that they not move is necessary to make the model closer in the situ) In addition, the input parameter calibration and other functions in the PFC simulation are more complicated than the continuum approach Further implementation of porosity value for different layers in hydrological approach and consideration of reliable vegetation to control the slow movement will be carried out based on this result 45 Slope movement monitoring by using extensometer and pipe strain-gauges as well as the application of PFC model to colluvial soil creeping are two of the new monitoring methods as well as the new model in this field of research Some experiences will be taken out from this project for the next monitoring and model application activity, especially in relation to monitoring and modeling of colluvial soil movement 46 Curriculum Vitae Name Nguyen Dinh Tu Gender Male Marital status Single Date of Birth 09 01 1978 Native city Thanh Hoa Nationality Viet Nam Background Education B.Eng (Geology and Petroleum), Ho Chi Minh City University of Technology, (1996-2001) M.Eng (Geology and Petroleum), Ho Chi Minh City University of Technology, (2001-2003) Current Education Ph.D sandwich student (under JICA - AUN/SEEDNet) (Gadjah Mada University, Indonesia + Kyoto University), Dept of Geological Engineering, Faculty of Engineering, Yogyakarta, Indonesia Work Experience Assistant Lecturer (2001-2002) and Lecturer since 2002- up to now, Faculty of Geology and Petroleum, Ho Chi Minh City University of Technology Previous Works PAPERS Tu, N.D., 2001, Investigating and evaluating landslide activities of Big and Small mountains-Vungtau City Studying its affects to urban planning and development of Vungtau City, The 3rd Young science workshop, held in Ho Chi Minh City University of Technology Ky, N.V., and Tu, N.D., 2002, Estimating underground water capacity in basalt rock for fresh water rural programme in Binh Phuoc province, The 7thScience – Environment Conference of East-South provinces of Vietnam Ngo, D.V., Ky, N.V., and Tu, N.D., 2003, Necessity and development capacity of subsurface structures in urban areas of Hochiminh city Journal Science and Technology Development of Viet Nam National Universtity of HCMC, Volume 6, Number 5&6/2003 Ky, N.V., and Tu, N.D., 2003, Hydrogeology charactersitics of Dongnai-Saigon river system Journal Science and Technology Development of Viet Nam National Universtity of HCMC, Volume 6, Number 11/2003 Tu, N.D., 2003, Some notes when to build bored pile in Vietnam, The 4th Young science workshop, held in Ho Chi Minh City University of Technology RESEARCH PROJECTS Ky, N.V., Hung, D.T., Tu, N.D., el al., 2001, Analysing and evaluating geological characteristics and its affects on the formation and restoration the underground water quality in the Dong Nai – Sai Gon valley – National project Ky, N.V., Hung, D.T., and Tu, N.D., 2003, The mechanism forms saline zones of the North of Mekong river area - Ministry project Tu, N.D., 2003, The roles of Evolution history and paleogeographic condition in Quaternary to the formation of groundwater quality of upper Pleistocene Holocene aquifers in Tra Vinh-Ben Tre provinces, Research project of Ho Chi Minh City University of Technology DISSERTATION Tu, N.D., 2001, Investigating and evaluating landslide activities of Big and Small mountains-Vung Tau City Studying its affects to urban planning and development of Vung Tau City, Bachelor thesis, Ho Chi Minh City University of Technology Tu, N.D., 2003, The roles of Evolution history and paleogeographic condition in Quaternary to the formation of groundwater quality of Pleistocene aquifers in provinces of Cuulong delta, Master Thesis, Ho Chi Minh City University of Technology PUBLISHED PAPERS Tu, N.D., Trung, N.M., Karnawati, D., Hendrayana, H., 2005, Hydrological Characteristic at Km 15.9 Kalibawang Channel, Kulon Progo, Yogyakarta, Indonesia, International Symposium on Earth Resources Engineering and Geological Engineering Education, Thailand Tu, N.D., Karnawati, D., Suryolelono, K.B., Hardiyatmo, H.H., Hendrayana, H., and Aoki, K., 2006., Slope hydrology and rainfall monitoring result at Kalibawang Irrigation channel, Km 15.9 Kulon Progo, Yogyakarta, Indonesia, Symposium on Geotechnical Hazards, Prevention, Mitigation and Engineering Response April 24th – 27th, 2006, Yogyakarta, Indonesia Tu, N.D., Trung, N.M., Karnawati, D., Hendrayana, H., and Aoki, K., 2006, Some preliminary monitoring results of slope creeping on colluvial deposits at Km 15.9 Kalibawang irrigation channel, Yogyakarta, Indonesia, International Symposium on Earth Resources Engineering and Geological Engineering Education, Yogyakarta Tu, N.D., Karnawati, D., Suryolelono, K.B., Hardiyatmo, H.H., Hendrayana, H., andAoki, L., 2006, Slope movement monitoring at Kalibawang Irrigation channel, Km 15.9 Kulon Progo, Yogyakarta, Indonesia by using Extensometers, International Symposium on Earth Resources Engineering and Geological Engineering Education, Yogyakarta Tu, N.D., Aoki K., Mito Y., Suryolelono, K.B., Karnawati D., 2007, Slope movement monitoring using strain-gauges at Kalibawang Irrigation channel, Km 15.9 Kulon Progo, Yogyakarta, Indonesia, International rock mechanic journal of JCRM Japan [...]... creeping on tropical soil to establish slope modelling for predicting mechanism of slope failure in Kalibawang, Indonesia, and the other area have the same conditions as Vietnam 2 Km 10 Km 11 Aerialphoto of KALIBAWANG Km 9 Km 12 Kedungro Km 13 Km 14 Km 15 Km Km 17 Km 18 Km 19 Km 20 Progo/Tinalah rivers Km Kalibawang Channel Site for slope monitoring 100m Figure 1.1 Location of the study area 1.2 Authenticity... at Gadjah Mada University, Yogyakarta, Indonesia, have been studying about geology of Indonesia At this research area, Kalibawang Irrigation channel, Nimol (2005) studied about application of geographic information system (GIS) for landslide susceptibility mapping from KM 6 to KM 19, Veasna (2005) studied about process of rain-induced landslides at KM 15. 9, Su Su Kyi (2007) studied about slope stratigraphy,... shallow water surface at structured slope by soil/rock forming aquifer do not be depressed 2 Condition of deep-water surface but above water surface, there are aquifer hang 3 At slope, there are pipe or natural channel which indicate the stream is unidirectional of slope inclination Farm at saturated slope, for example effect of existence of rice field and drainage for domestic resulting porosity irrigate... phenomena for that area Slow mass movement, or creep (rates