| Grouting is defined as the injection of some grouting materials into cracks, fissures, cavities, voids and pore space to eliminate or to reduce water leaks and to increase strength in rocks or soil. Grouting rocks is a special technique developed in many countries with many applications. In fact, the important source of new energy is hydroelectric dams as water, which is precious and widely distributed on earth and, unlike any other mineral resources; it is an important element in the process of social and economic development.Therefore, the overall planning and management of grouting quality, quantities are very important for preventing loss of water through the foundation and to get high efficiency. Why do we do this research? We do this research because in arid and semi arid regions most of the countries such as Yemen, there is water scarcity and which requires the construction of several dams for water storage and therefore requires spending a lot of money for its construction. And despite all of these constructions, water has been leaking from dams, due to several factors, which includes low efficiency of grouting. The theoretical significance and application value is according to theory of grouting and grouting practice, there are relationships between degree of inject ability, particles sizes and breadth of fissure as presented in the equation below:This thesis consists of studying grouting technology methods in small dam in Yemen and other countries, experiments were carry out on curtain grouting technology for rock dam of Pushi river pumped storage hydro-plant in China, then it also consist the study of rheological behaviour and compressive strength of cement bentonite grouts slurry in laboratory, after that it studies relationship between high pressure responses and stable discharge, boreholes definition limits and injection permeability in the field. Finally, computational simulation was carried out on two cases, high pressure responses with water discharge and with liquid-solid.The aims of this thesis are to improve the efficiency of grouting and to reach the best economic solution. There are three basic grout systems used by several countries in grouting rocks dams. For grouting technology methods on small dams in Yemen, and the system of grouting design in Yemen consists of a mixer to mix grout materials such as cement and bentonite, injection pipeline to move suspension grout for injection, flow meter for flow measurement, pressure gauge which is a device used for measuring the pressure of liquid, bore hole drills, also it consists of pump pressure, pump water and so forth, ordinary concrete around the soil surface in order to install the grout pipe inside the bore hole drilling, above the soil surface there is grout pipe about0.5meter and0.5meter inside the borehole. The diameter of drilled borehole usually between5.1-10.16cm, grouting pipe diameter5-10cm and the tall pipe is not more than1.20meter, between30-50cm inside the borehole but the open voids and fractures are below the nozzle and is not in front of it which is a big disadvantage.In general, grouting systems of dams can be classified into three types according to the delivery mechanism, which are single fluid, double fluid and triple fluid. System of grouting design in China, that there are several grouting systems such as:A single fluid; double fluid and triple fluid.Grouting systems of Pushi river dam is classified into single fluid according to the delivery mechanism. The open rock fracture or voids is to be in front of the nozzle, which leads to high injection efficiency, unlike system of grouting design in Yemen. This system is famous for use in loose sandy soils and it is less expensive compared with other systems. The grouting method from down to up inside the boreholes.Presently the grouting method and grouting system, the mud preparation and changing the slurry standard for curtain grouting are according to the designed requirements using the bottom-up stage grouting method, on the development of rocks joints. The segment length for curtain grouting is in the range of5-6meter, exceptional circumstances can be suitably scaled or lengthen, but not more than10m. The grouting system of Pushi river dam consist of different pump, grouting mixer, high pressure tubing, additional water, grouting pump, automatic recording, a slurry tripod, flow meter, pressure gage, drilling rig, concrete cover, filling, straddle packer and grouting section.That the references value of pressure grouting at different sequences boreholes which range between3000000Pa to3500000Pa, if total depth is greater than30m. The water cement ratio was determined by the grouting test or project approved by supervisor, grout slurry shall be thin to thick for water cement ratios by5,4,3,2,1,0.8,0.6or0.5. If grouting pressure remains constant, injection rate continues until it decreases without changing water cement ratio. In case the quantity of grouting slurry already amounted to more than300litter or perfusion time already30min and in case of the grouting pressure and injection rate had not significant change, the water-cement ratio for grout slurry was replaced. If the injection rate is more than30L/min according to the specific situation of construction, the grout slurry is thicker.Technology methods in other countries case study Shahriard dam at Iran:there are three famous grouting systems i.e.:A single fluid, double fluid, triple fluid. The single fluid system it consists of grout material, double fluid system it consists of grout material and air, also triple fluid system which consist of grout materials, compressed air and water. In case of the study of rheological behaviour and compressive strength of cement bentonite grout slurry by water:cement:bentonite (5%and0) and measure viscosity, fluidity, bleeding, temperatures and compressive strength at7and28days for bentonite (5%and0%) too, some equation for calculation were used such as:For compressive strength:breaking cylindrical concrete specimens in a compression testing machine and it is calculated from the failure load divided by the cross sectional area resisting the loads as presented in this equation: For wet specimens, were first immersed in water for28days before testing, in case of viscosity, according to API standard which allow one quart (946ml) of slurry to flow Out of the funnel and is expressed as time in second. Also we can calculate the viscosity by MPa.s using an equation: u1=ρ(t-25) For fluidity, it is define to the tendency to allow of liquid flow easily, it is an important relative factor to grout mix designs, also if the flow rate is considered constant during the test, it could be calculated from the initial fluid filling level as presented in this equation For test procedures for determine rheological behaviour was used different quantities of water content such as5,4,3,2,1,0.9,0.8,0.7,0.6,0.5,0.4kg, with lkg cement for all ratios at bentonite equal0.05and with bentonite equal zero. The bleeding of water from slurry was calculated from the formula as presented in this equationThe calculation of bentonite ratio is presented in an equation below Bentonit=5%(Water+Cement) In case of compressive strength, the same treatment for compressive strength at7and28days but with ratios1,0.9,0.8,0.7,0.6,0.5,0.4.For studying the relation between high pressure and water discharge response is one of the most debated issues concerning rock grouting, the study was carried out in Pushi river dam, in China, the total reservoir capacity is13510000m3. In this study, the investigated region contains soil with sediment from the land surface to6m deep, which consists of upper proterozonic hybrid granite with insert some diorite for most of boreholes in the down borehole, also it contains migmatite mixing in granite, The type of granite is hard rock and the rock abrasiveness is medium to low.In case of water pressure test was carried out in foundation of dam using drill borehole. Drilling rig is placed over the borehole collar for tripping down and hole tools necessary for conducting the tests, packer permeability test, high-pressure tubing, drill pipe, drilling bit sizes (φ150,φ110,φ76) mm for drilling soil and rocks, also pressure gauges, pressure transducers, flow meter, pressure generators,3SNSA high pressure pumps for the hydraulic fluid pressure, TS intelligent automatic recording to a record data, XTF-2hydrualic rubber double can bear the pressure of3000000Pa and could be expansive rate of200%, orienting tool, also used was water with the same viscosity and also used for drinking and others. The number n of Lugeon unit is measure of permeability obtained from pump in water test is established as presented in this equationTwo cycle recording was used, for the first cycle the straddle.packer pressures at [1125000,2316000,3205000,4120000,5133000,6205000,5253000,4443000,3418000,2515000,1327000] Pa and second cycle are [1437000,2328000,3415000,4441000,5419000,6461000,5345000,4418000,3369000,2350000,1435000] Pa, representative, at depth42to47m. In case of simulation between pressure and water discharge in order to simulate, gambit program was used to create and mesh model; and was used fluent to examine the tutorial. Also used was ansys program to create the relationship between pressure and Volume of Fluid (VOF).Thus this research includes studying simulation on high pressure responses with volume of fluid, the different parameters affecting the deformation control of it analysis and critical point for high pressure of the best test permeability parameters by using numerical simulation, the pressure vector and volume of fluid at number of time steps was (2.0000e-01) and max iterations for time step was50, with pressure water at [1125000,3205000,41200000,5133000, and6205000] Pa, and simulation high pressure responses with discharge liquid-solid at [1125000,3205000,41200000,5133000, and6205000] Pa.For estimating the possible velocity of the inter face and the grid cell dimension time step was calculated by equations as follow:Then a velocity appears with different pressures after that iteration, finally it has been shown that the contours appear at different pressures.Drilling methods can also alter physical, biological, and chemical properties of soil and rocks. There is a strong relationship between drilling and rocks properties such as permeability. Drilling techniques have developed rapidly with several application fields such as borehole drilling for grouting, core exploration, water pressure test and foundation.Thus this research also includes studying boreholes deviation limits and permeability at the depth of100m by monitor drilling process for borehole, evaluation of it according to China standards specifications of cement grouting borehole deviation (DL/T5148-2001). Also this study was carried out in Pushi river dam too, in China. Vertical deflection rate is the boreholes deviation from the bottom. The drilling surveying process is important in optimizing drilling operations and increasing the productivity of drilling process. The real deviation from borehole drilling design which was measured based on the following formulas: d=L1Sinθ Tanθ=d/LThe technical specifications for construction of grouting drilled boreholes, which has been checked to depth of desired from edge of casing. It indicates the real depth of well and the allowable deviation by meter. First a grouting boreholes was selected in compliance with the legal documents, road was constructed and the derrick was erected. Since water is important in drilling holes for mixing slurry so that it can be hauled into the location by water pumped method, the drill rig type XY-2PC was to put in the site of borehole.However, the use of drilling bit with surface shape (V-ring) was used. Free crashing space was created for fast drilling with different diameters. Grouting testing for the granite rocks uses straddle packer at different pressures, the unit Lugeon is defined as the flow rate of water along per meter of test segment under the pressure of water injection of1,000,000Pa.The Lugeon value is measured with the Lugeon test, the requirement of grouting such as size of particles and design grouting, it is necessary to know the data by the Lugeon test. The number N of Lugeon units is a measure of permeability value from pump-in water test as presented in this equation Moreover, the results from three experiments, two in the field, one in the laboratory, and simulation have shown that. In general grouting systems of Pushiriver dam is classified into single fluid the advantages use possible with loose sandy soils, the grouting process are grouting materials and impossible remove soil and replace with grout and less expensive compare with double fluid system and triple fluid system, it need highly skilled.Grouting system in Yemen depends on a delivery mechanism of grouting system which is classified into very near from the single fluid system and the advantages and disadvantages system of grouting design in Yemen as follow:Advantages:●Less expensive;●Using for difficult region;●It does not need highly skilled.●Disadvantage:●Impossible to remove soil and replace with grout; ●It does not allow air to exit from the well which results in opening new fractures and voids;●Difficulty in installing on soil;●External explosions in embedded concrete which installed grouting pipes;●Low efficiency for grouting system;●To cause high sediment on bottom of boreholes;●Difficult to use for most type of soil;●The open fracture or voids is below of the nozzle and is not be front of it, which leeds to lack injection efficiency;●It is not containing several nozzles. However, a sandy soil is widely distributed in Yemen and more dams are not up to25meter so that the single and double fluid systems are suitable solution for jet grouting in Yemen. Also results have shown that, there are effect of loading speed on the plate ultimate strength of steel plates subjected to dynamic axial compressive load, the compressive strength test results on the samples tested, in cases of7and28days.For7days at B=5%for ratios (0.4:1,0.5:1,0.6:1,0.8:1and1:1) are (2675.59,2334.45,594.65,270.40and397.5) kN/m2For7days at B=0for ratios (0.4:1,0.5:1,0.6:1,0.8:1and1:1) are (2917.55,2384.60,973.24,488.29and468.56) kN/m2For28days at B=5%are (3344.50,2918.10,743.31,731.12,339.50,731.12and530.00) kN/m2for ratios (0.4:1,0.5:1,0.6:1,0.7:1,0.8:1,0.9:1and1:1) but the compressive strength at0.8:1:0.05was the least values.For28days at B=0for ratios (0.4:1,0.5:1,0.6:1,0.7:1,0.8:1, and1:1:) are (3513.70,2981.75,1216.55,425.33,615.20and585.70) kN/m2It was concluded that the compressive strength at28days for B=o is higher than at28days for B=5%, except ratios of (0.7:1and0.9:1). Also there is a direct correlation between the amount of water in the sample and the compressive strength with decrease quantity of water increase compressive strength. It was also concluded that in case add bentonite5%to cement no affect on increase compressive strength except ratios (0.7:1:0.05and0.9:1:0.05). For measure fluidity the results have shown there is effect on bentonite flow of suspension except to0.9:1:0.05also flow time and dynamic viscosity of slurry grouting increases with decrease water ratio to cement: bentonite (5%) except to0.9:1:0.05. W:C:B ratio of0.81:0.05viscosity and flow time are low whereas the viscosity is much higher for a0.6:1:0.05but for ratios0.5:1:0.05and0.4:1:0.05doesn’t flow. Also that low viscosity and low flow ability grouts are effect for injection into fissures. Voids, and joints but high viscosity grouts might be effect to limit flow of slurry to fill it. Also the test-Results showed there is effect on flow time and plastic viscosity with using B=5%than B=0%. For W:C:B ratios up to1:1:0.05have high water content as follow:(5:1:0.05,4:1:0.05,3:1:0.05,2:1:0.05), but the mixing ratios less than1:1:0.05have low water. The process of bleeding from all these ratios studies have high bleeding during one hour from three hours but for less than6%light bleeding within two hours. Also ratio2:1:0.05was the high time period until the bleeding stop but no bleeding from various occurred for ratios0.4:1:0.05and0.5:1:0.05with using (B=5%and B=0).Results have shown that, with different water ratios, cement and bentonite have marked effects on dynamic viscosity, fluidity, bleeding and temperature, and to effect on quantity bleeding of water from slurry and thickening time. But decrease water content ratio can improve the stability of slurry, but reduce its movement and this in turn has affected the process injection of rocks. Also found was that W:C:B less than0.6:1:0.05may cause agglomeration of solid particles. The specific heat of water is constant but the cement specific heat for OPC past increased with temperature to an extraordinary extent.Moreover, with development of grouting technology the proportion of deep well is increasing, hence big temperature difference from top and bottom, which effects of the injection slurry. Also if cement and bentonite were mixed with water the temperature rise occurs immediately and steady state temperature, then an appreciable and continues at diminishing rate for20minutes. The temperature is rise at B=5%than B=0and the temperature at0.4:1is higher than5:1. See chapter three.Also the Results have shown that, for relationship between high pressure and water discharge response, there is a relationship between high pressure and water discharge, the permeability remains high when the pressure is reduced.In case using high pressure the fissures are widened and others are opened. For pressure up to5133000Pa, the permeability was decreased and the large seepage was discharged1.220L/min; if increasing pressure to6205000Pa, the flow rate value is24.500L/min, with rate increase up to20.08once this explains the fissures of rocks are widened, or the pre-existing fractures opens or both, it was concluded that the critical pressure point in pressure axis was at5133000Pa. If breakdown pressure water to5235000Pa, the water discharge decrease to19.905L/min, but if water pressure decreases to1327000Pa, the water discharge is4.020L/min. In case of the material filling the fissures after the fracture has closed is being eroded during the test, the permeability increases exponentially with increasing water pressure but the permeability remains high in case of the pressure is reduced and was noted at value of6461000Pa. Suddenly increasing seepage discharge to32.45L/min, this is due to expansion and extension of some fissures. After reaching the maximum injection flow rate, the pressure is decreased progressively in a stepwise manner, so that as to reach complete closure of the fracture. See chapter four.High pressure and water discharge simulation are very important for checking rock foundation; it may have a negative impact such as opening of new crack or expansion result in more flow of water. The different parameters affecting the deformation control of VOF analysis and critical point for high pressure of the best test permeability parameters by using numerical simulation. Volume of fluid multiphase model to solve problem of cracking in rocks. The results show experiment (First Cycle) and numerical simulation results were carried out to study the relation between high pressure and volume of fluid; the agreement between simulation and experiment at the critical high pressure point is5133000Pa. Also the results show that in case of increasing pressure to6205000Pa is similar to the pressure at5133000Pa. Using the same simulation method steps by using liquid-solid at different pressure levels such as:1125000,3205000,4120000,5133000and6205000Pa shows that the results in case of using solid-liquid indicate no critical point between1125000and6205000Pa, which is opposite of using case water at5133000Pa, with the flow time increasing significantly. But in cases of1125000,3205000and4120000Pa, we get the same results for both cases. See chapter6.The subsurface information is needed for the plan and success permeability program depending on several core drilled wells in combination with digital imaging results. According to monitoring drilling deviation for measuring grouting permeability at grouting rocks for efficient drilling and injection test, that there are relationship between them and depth, in this site of this study, also the results data of study a relationship between boreholes deviation limits and permeability indicates that the study grouting borehole (one row) with depths (10,20,30,40,50,56.99,60.30,70,80,90,100) m, and deviations as follow (0.00,0.00,0.00,0.00,0.010,0.020,0.020,0.025,0.035,0.041,0.047,0.050) m, the maximum depth was100m and the maximum deviation was0.05m this values of deviations are within the allowable range according to specifications of cement grouting boreholes deviation (DL/T5148-2001), in China. Also the correlation between depths and deviations is not strong and the borehole drift was reduced, we can explain careful drilling and high of drilling equipment.At depth between40-41was started drifting, also during drilling by drilling fluid method a lot of water be leaking at depth21-22m and at40-41is a first indicator to there is relationship between drilling and permeability.Using the borehole camera for the site of crack and fracture at depth range between21-22inside the rock, the lithology description to indicate the L of fracture is1.37to9.66cm and thickness is0.09m in this site of this study. L of fracture at depth between40-41m is1.915cm and the thickness of fracture is0.07m, the length and thickness of fracture at20to21m are larger than at40-41m. There is a relationship between rock permeability by Lugeon and the depth by meter. LU decreases with the increasing depth in general but at the depths between40-41m the permeability was1.5LU but at21m, the LU values are the largest (2LU) in this site of this study but the injection permeability is still very low, also that after50m was very low permeability and the permeability decreases with depth. In case of depth between40-41m, the curve of injection permeability was changed. During drilling, there was a lot of water losing at depth21-22and40-41m, the drift was started at40-41m, and this is indicators to existence of a relationship between drilling and permeability at depth40-41m, which through drilling the site of fracture was predicted. There is a relationship between the drilling and permeability and there are technical, technologies, good drillers and geological, which help to get good efficient drilling, the results effect on efficient measuring rocks permeability in this place of this study. Also during drilling the site of fractures was predicted; also the injection permeability is low in granite rocks and the permeability decreases with depth. Finally this research concluded the following findings:1. The water with different ratios when make with cement and bentonite had a marked effect on:Dynamic, viscosity, fluidity, temperature, bleeding, but in case add bentonite5%to cement not be affected the increase compressive strength except ratios (0.7:1:0.05and0.9:1:0.05).2. There is a relationship between pressure and water discharge, the critical point was at5133000Pa for experiment and numerical simulation but for simulation with using solid-liquid indicate no critical point between1125000and6205000Pa.3. There is relationship between drilling fluid and permeability, which means during drilling we can predict the site of fractures and permeable grouting.4. A sandy soil is widely distributed in Yemen so that the single and double fluid systems are suitable solution for grouting design in Yemen. |
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