Numerical Modeling of the Effects of Toe Configuration on Throughflow in Rockfill Dams

The rockfill toe structure situated within the downstream slope of rockfill dams is an integral part of a defense mechanism safeguarding the dam structure in throughflow situations. Recent studies have concluded that the rockfill toe structure can have significant impacts on throughflow development and stability of rockfill dams under scenarios of accidental throughflow caused by overtopping of the dam core. The ability to numerically model the effect of various toe configurations on flow through rockfill dams can support the design of effective toe drainage structures for rockfill dams. Development and calibration of a reliable numerical modeling tool in this regard has been challenging owing to lack of availability of extensive datasets from physical modeling investigations. This study further employs datasets gathered by a recent physical modeling study investigating the effects of various toe configurations on throughflow development in rockfill dam models. A commercial numerical seepage modeling tool with an option for non-Darcy flow was calibrated against the datasets with good calibration metrics. The study is novel in providing a rare report on the usage of this option. The calibrated tool can further be employed to carry out a wide array of simulations to arrive at an ideal design for a toe structure for rockfill dams and for assessment of hydraulic performance of toe structures.

ANALYTICAL MODEL OF THE PLANETARY BOW SHOCK FOR VARIOUS MAGNETIC FIELD DIRECTIONS BASED ON MHD CALCULATIONS

Study of physical processes in plasma near planets often requires knowledge of the position and shape of the planetary bow shock. Empirical models are usually used since theoretical MHD and kinetic models consume too much computer time and cannot be used to track fast processes. M.I. Verigin proposed a semi-empirical approach based on the use of exact theoretical expressions with a small number of parameters, which have a clear physical meaning. These parameters are estimated by fitting experimental data or detailed MHD calculations. A model of the bow shock near an arbitrary-shaped obstacle has previously been developed for a gas-dynamic flow. This model can be applied to any sonic Mach numbers and large values of the Alfven Mach number. In addition, the asymptotic Mach cone — the angle of inclination of the shock wave at an infinite distance from the planet — has been calculated analytically in the MHD approximation. In this paper, we propose a model of the bow shock for any direction of the magnetic field with respect to the upcoming flow and for any Mach numbers. Parameters of the model are the distance of the nose point from the obstacle, radius of curvature and bluntness of the bow shock at the nose point, a parameter related to the transition to the asymptotic downstream slope of the shock, and a skewing angle appearing when the interplanetary magnetic field is directed at an angle to the solar wind velocity.

ANALYTICAL MODEL OF THE PLANETARY BOW SHOCK FOR VARIOUS MAGNETIC FIELD DIRECTIONS BASED ON MHD CALCULATIONS

Study of physical processes in plasma near planets often requires knowledge of the position and shape of the planetary bow shock. Empirical models are usually used since theoretical MHD and kinetic models consume too much computer time and cannot be used to track fast processes. M.I. Verigin proposed a semi-empirical approach based on the use of exact theoretical expressions with a small number of parameters, which have a clear physical meaning. These parameters are estimated by fitting experimental data or detailed MHD calculations. A model of the bow shock near an arbitrary-shaped obstacle has previously been developed for a gas-dynamic flow. This model can be applied to any sonic Mach numbers and large values of the Alfven Mach number. In addition, the asymptotic Mach cone — the angle of inclination of the shock wave at an infinite distance from the planet — has been calculated analytically in the MHD approximation. In this paper, we propose a model of the bow shock for any direction of the magnetic field with respect to the upcoming flow and for any Mach numbers. Parameters of the model are the distance of the nose point from the obstacle, radius of curvature and bluntness of the bow shock at the nose point, a parameter related to the transition to the asymptotic downstream slope of the shock, and a skewing angle appearing when the interplanetary magnetic field is directed at an angle to the solar wind velocity.

SETTLEMENT MONITORING OF THE EARTH DAMS BY PERFORMANCE PERIODICAL TOPO-GEODETIC MEASUREMENTS

The paper presents the current way of elaboration of the topographical and cadastral documentation needed in the process of tracking the behavior of hydrotechnical constructions such as earth dam. The studied area is represented by the accumulation of Pârcovaci located in the Deleni territorial administrative unit in Iași county. Using topo-geodetic measurements the magnitude of the vertical displacement of the studied construction were determined. The measurements were performed during the exploitation period of the dam, during 23 series of observations. Thus, there were highlighted the displacements of landmarks located on coping dam, downstream slope and outlet tower. Charts of evolution over time of vertical deformation have been made according to field observation. Also, the suface of the land corresponding to the whole of the accumulation of Pârcovaci was registered at Office of Cadastre and Real Estate Advertising Iași, through first registration documentation. This has made precise spatial delimitation of the set of lands and construction of studied area, and the whole land was recorded in the land book by assigning a unique cadastral number.

PERENCANAAN EMBUNG GUWOREJO KECAMATAN TAROKAN KABUPATEN KEDIRI

In dry season Tarokan Sub-district of Kediri, often suffers from drought, so a small dam (embung) was required. The objectives of the study are to determine the dimension of the dam, its spillway and to analyze its stability. The required data were of rainfall, topographic maps, soil, and population.The initial design was hydrologic analysis by finding out the planned discharge Q50 and determining the water volume of inflow. To determine the effective catchment ponds, capacity analysis using topographical data and comparing the volume of water available. And analysis of spillway to determine the flood water level.The analyses result, the amount of the water needs of a population of 258.854.400m3, and the magnitude of the draft Q50 discharge of in 4.027 m3/sec (The room for sediment is 29,234.9 m3 at elevation 1 m from the bottom of the pool); 390,000m3 effective capacity at +131.75 elevation, and flood water level at +132.75 elevation. The dimension of embung main dam is 6 m deep; embung crest at +133.00 elevation ; 3m wide embung crest ; 1:3 upstream slope; 1 : 2.25 downstream slope ; 10 m wide spillway channel 1 : 1 slope of wall of spillway channel ; and crest of spillway at +131.75. Geostudio software was used to calculate the figures safety against sliding. Keywords: embung, spillway, embung dimensions, slope stabilty

PERENCANAAN TUBUH BENDUNGANAIR LUAS KABUPATEN KAUR PROVINSI BENGKULU

The purpose of this study was to plan the dimensions of the dam body that is technically feasible to build, as well as secure the stability. Flood discharge plan used amounted to 1,152 meters cubic/ sec with a return period of 1000 years. Based on the analysis that has been done, get a plan of flood water level is + 303,22 meters, surveillance obtained high of 3,0 meters, the body of the dam crest elevation gained + 306,22 meters high dam that is obtained by subtracting the height elevation of the peak body dam with a base elevation of the dam is 56,16 meters, width of the dam crest beacon of 11.0 meters, rockfill the upstream slope of 1:3 and for rockfill downstream slope is 1: 2,.25. Using the scheme of depression line formation with drainage leg with a graphic way, do not occur out of the body dam seepage and flow filtration capacity value of the calculation, Q = 9,553 x 10-5 meters cubic / sec, smallest than 2% Qinflow mean = 5,785 mmeters cubic / sec, dam secure against flow filtration. The stability of the main dam of landslide with the value of safety factor in a variety of conditions, namely dams both empty and fully charged in a normal state or an earthquake, for rockfill dam by calculating the weight of the dam, sliding moment, pore water pressure and earthquake loads. Using the method of slices Fellenius glide plane, the value obtained above safe rate (1,2), the planneddam safety to landslides

Dam-break on an idealised hill side: Preliminary results of a physical model

The aim of this work is to study the propagation of dam-break waves along a hillslope by mean of a physical model (basically i.e. a 3 x 4 m2 plane set downstream of a reservoir) build up in the Hydraulic Laboratory of the Politecnico di Torino. We want to recreate the water surface, to assess the shape of the flooded area and the arrival time of the wave front. The measurement facility is a high resolution CMOS camera. We measure the water height by linking the intensity of the pixels in the acquired images to the real water depth. Preliminary quantitative results are given for the 0°downstream-slope scenario and qualitative results are presented for the case of downstream inclined plane.