In this study, fracture grouting technique of saturated, granular soils of different fine content were investigated. Model tests were carried out by using fluid particulate grouts namely micro fine cement and ordinary portland cement grouts. Basically, relationships were obtained between soil conditions (grain size distribution, relative density, overburden stress) and grouting parameters (type of grout, grouting pressure, amount of injected grout, rheological properties of the grout or water/solids ratio). At the end of the tests the soil specimens were exposed and the final grout shapes were observed and correlated with the grouting parameters. Response of soil specimens to grouting process under different grouting pressures and grout compositions was analyzed. Amount of heave occurred at the top of the specimen during injections was recorded at each test. Micro fine cement grout and ordinary portland cement grout showed significant differences rheologically. Micro fine cement grout, with much higher Blaine fineness, lower specific gravity, lower viscosity and cohesion, lower bleed and filtration coefficients, made it possible to fracture the fine sandy soils of different fine content. Results of tests performed with micro fine cement grouts show that fracturing pressure generally decreases with an increase in the water content of the grout but generally increases as the fine content of the soil increases. A higher relative density of the soil increases the fracturing pressure significantly. The volumes of grout injected into soil specimens until fracturing show an increasing tendency as the water/solids ratio decrease. Ordinary portland cement grout, on the other hand, exposed to high pressure filtration during grouting in relatively clean sand and addition of some amount of kaolinite or fines is required to reduce the filtration percentages during grouting in order to fracture grout the sandy soil. Filtration due to high permeabilities results in accumulation of cement particles around the injection point and grouting tends to take a form similar to compaction grouting.

No description available.

QC 20100714

With the development of urban areas and the constant need to change or improve the existing structures, a need for creative and less destructive soil reinforcement processes has occurred. Jet-grouting is one possible ground improvement technique. The behavior of the soil improved by jet-grouting is still not well understood. In this thesis, the mechanical behavior of the injected soil is modeled in order to determine the different parameters needed for the engineering design of a soil reinforcement based on jet-grouting. At first several models are presented in order to determine the extent of the injected zone within the soil mass, based on engineering parameters (cement poroelastic properties, injection rate). A model based on an energetic balance is proposed to compute the lower bound of the injection radius. The second part of the thesis focuses on the characterization of the uniaxial compressive strength of the soilcrete created in the injected area determined in the first part. Three different methods have been adapted to the problem. A hollow sphere model has been calibrated against published data. After calibration, both Eshelby's and averaging methods proved to provide results close to the reference data. The last part of this report presents numerical studies of the pile and of a group of piles. The study of the group of piles focuses on the effect of arching between soilcrete columns to reduce the vertical settlements due to urban tunneling at the surface. It appears that the values obtained for settlements in the presence of jet-grouted columns are much less important than in usual tunneling problems (with no reinforcement).

Over the past years, levee failures during floods have caused significant losses of lives and properties in the nation. Majority of these failures were induced by seepage through granular foundation soils underneath the top soil on which the levees were built. One of methods to mitigate this phenomenon includes the treatment of the granular soil deposits with an engineered fluid delivered by permeation (permeation grouting), resulting in a less pervious deposit. Since the conventional cement-based suspensions and chemical solutions may cause groundwater contamination due to long term reaction with groundwater, clay suspension such as bentonite suspension can be an alternative in terms of environmental friendliness and long-term safety. Moreover, the suspensions, after being permeated, are expected to be stable in the pore space due to the thixotropic nature of bentonite. The main challenge in this approach is being able to permeate a concentrated suspension through the pores of a granular material. To achieve a significant reduction in the hydraulic conductivity, concentrated bentonite suspensions should be used; however, concentrated suspensions can have low mobility, resulting in a low penetration depth and little practical application. The main objective of this study is to investigate the permeation of concentrated bentonite suspensions by controlling their rheological properties. The first portion of this research focuses on measuring the rheological properties of the various engineered bentonite suspensions over time. The second point of focus of this research is the parameters affecting the flow of the bentonite suspensions through granular soils, and the final focal area is determining the hydraulic performance of the grouted granular soils. In order to achieve these objectives, an experimental program was developed in this research. First, rheological tests were performed with the bentonite suspensions with and without various concentrations of sodium pyrophosphate (SPP); SPP is an ionic additive that is used to reduce the initial yield stress and viscosity of bentonite suspensions. A stress controlled test with the vane geometry produced rheological parameters with a minimal disturbance. Suspensions were stored in sealed cups and tested at various times to measure the long term thixotropic changes in yield stress and viscosity. Second, the various concentrations of the bentonite suspensions were injected at a constant pressure through clean sands which were prepared at various conditions (relative density, fine contents, and grain size) in order to investigate soil and suspension parameters affecting the flow of the bentonite suspensions. The results from these experimental tests were utilized to develop a groutability criterion of bentonite suspensions for practical purposes. Finally, the saturated hydraulic conductivity of the treated soils was measured using falling and rising head method. The traditional concept of “clay void ratio” was re-examined. The results from this study showed that the modified bentonite suspensions could be used as an alternative grout in permeation grouting to improve hydraulic performance of the permeable granular soils. / text

Slurry wall is a geotechnical engineering application to control the migration of contaminants by retarding groundwater flow. Sand-bentonite slurry walls are commonly used as levees and containment liners. The performance of bentonite slurry in sand-bentonite slurry walls was investigated by studying the rheological properties of bentonite suspensions, the penetration length of bentonite slurry into clean sand, and stability of the trench under in-situ hydraulic gradients. In this study, the rheological parameters of bentonite suspensions were measured at various bentonite fractions by weight from 6 to 12% with 0-3% of sodium pyrophosphate; an ionic additive to control the rheological properties of the bentonite slurries. The penetrability of the bentonite slurries through Ottawa sand was studied by injecting the slurries into sand columns at different bentonite fractions. The injection tests were performed with the permeameters having different diameters to eliminate any bias on test results due to the different size of permeameter. An empirical correlation for predicting the penetration length of bentonite slurry based on apparent viscosity, yield stress, effective particle size, relative density, and injection pressures was updated by taking into account the effects of the permeameter diameter size. Moreover, the stability of sand-bentonite slurry walls was inspected by studying the hydraulic performance of sand permeated with bentonite suspensions under increasing hydraulic gradients. The critical hydraulic gradient at which washing out of bentonite suspensions is initiated was examined. For specimens with bentonite contents less than the threshold value, the flow occurred through the sand voids and minimal washing out occurred. On the other hand, when the bentonite content was high enough to fill up all the void space between the sand particles, the flow was controlled by the clay void ratio. In this case, washing out did occur with increasing gradients accompanied by an increase in hydraulic conductivity. Accordingly, a relation between the yield stress of bentonite suspensions and the critical hydraulic conductivity was developed. / text

Baigiamajame magistro darbe apžvelgiami pamatų ir pagrindų stiprinimo būdai. Laboratorijoje atliktas sustiprinto natrio silikato tirpalu grunto tyrimas, nustatyta jo mechaninių savybių priklausomybė nuo bandinių kietėjimo laiko. Nagrinėjamas pagrindų injekcijos metodų naudojimas pastatų rekonstrukcijai. Taikant COSMOS programinį paketą įražos apskaičiuotos šiais atvėjais: 1. Sudarius erdvinį grunto masyvo modelį, kai gruntas po pastato pamatu nesustiprintas; 2. Kai gruntas sustiprintas porų injekcijos (angl. Grouting) metodu; 3. Kai gruntas sustiprintas srautinės injekcijos (angl. Jet-grouting) metodu. Palyginamas įtempių sklidimas ir poslinkių kaita grunte (smėlis). Gautų atsakymų analizavimas. / Foundations and grounds strengthening methods were reviewed in this Master thesis work. The test of soil strengthened with sodium silicate solution was accmlished in the laboratory. Dependence of soil mechanical characteristics from samples solidification time was ascertained. Usage of grounds injection menthods for reconstruction of buildings was investigated. Applying COSMOS program package the efforts were estimated in such cases: 1. forming the dimensional model of soil solid when the soil under the foundations of the building is not strengthened; 2. when the soil is sthrengthened using the Grounting method; 3. when the soil is strengthened using the Jet-grounting method. Spread of strains and vicissitude of shifts in the soil (sand) were compared. The analysis of obtained results was made.

“Real time grouting control method” är ett koncept för att övervaka och bedöma spridningen av injekteringsbruk under injektering. Målet är att kunna använda penetrationsavstånd som stopkriterium och att kunna övervaka hur injekteringsarbetet fortskrider i realtid, vilket skulle göra injekteringsarbetet mer tids- och kostnadseffektivt. Teorin har prövats med data från ett tunnelprojekt i Sverige med kristallint berg från prekambrium-eran, och med data från dammprojekt i Iran och Laos med sedimentärt berg, samtliga med lovande resultat. RTGC-teorin har nyligen vidareutvecklats, där bedömningar och begränsningar angående jacking föreslås, utifrån en kombination av injekteringstryck och spridning av injekteringsbruk. Teorin har  tvecklats både för elastisk jacking, där deformationer kan kompenseras för, och för plastisk jacking, där deformationerna är permanenta. Effekterna av höga tryck och jacking kan uppskattas och de eventuella negativa konsekvenserna kvantifieras. Mer specifikt ligger fokus på vilken påverkan sprickdeformationer kan ha på penetrationsavståndet och på transmissiviteten i en spricka. Syftet med detta examensarbete har varit att undersöka vilka effekter höga injekteringstryck har på injekteringsprocessen av en tunnel med avseende på jacking. I examensarbetet har teorin för RTGC använts för att analysera data från ett järnvägstunnelsprojekt i Norge, där betydligt högre injekteringstryck än i Sverige generellt sett används. Teorin har kunnat appliceras på data framgångsrikt, även om mindre anpassningar varit nödvändiga. Orsaken till anpassningarna är att teorin främst är utvecklad för ett mer eller mindre konstant injekteringstryck, samtidigt som ett varierande injekteringstryck i viss utsträckning använts i det norska projektet. Resultaten tyder på att det skulle vara möjligt att spara både tid och pengar med hjälp av RTGC, genom att minska åtgången av både tid och injekteringsbruk. Resultaten antyder även att höga injekteringstryck kan orsaka betydande jacking om geologin och sprickornas orientering och längd är ogynnsamma. Om och i vilken utsträckning jackingen påverkar den slutliga tätningen av bergmassan har emellertid inte kunnat studeras i detta projekt, då data kring inläckage ej varit tillgänglig vid genomförandet av analysen. Vidare visas, trots vissa antaganden och förenklingar i den geologiska modellen, att denna teoretiska modell möjliggör en bedömning av effekterna som injekteringstrycket har på det slutliga resultatet. Detta bör kunna användas för att välja ett optimalt injekteringstryck. / The “Real Time Grouting Control Method” is a concept for governing the grout spread during a grouting operation. The goal is to be able to use the penetration length as stop criterion and to be able to monitor the progress of the grouting operation in real-time, which would make grouting operations more efficient in terms of time and cost. The theory has been tested with data from tunnelling projects in Sweden with pre-cambium rock, and with data from dam projects in Iran and in Laos with sedimentary rock, all with promising results. Recently there have been developments in the RTGC-theory that propose jacking limits based on a combination of grout pressure and spread of grout, both for elastic jacking, where deformations can be compensated for, and ultimate jacking, where deformations are permanent. With the theory, the effects of high pressures and elastic jacking can be assessed, and the negative consequences of elastic jacking can be quantified. Specifically, the  focus is on the effect that fracture deformation may have on the distance that the grout penetratesinto a fracture, and on the transmissivity of a fracture. The aim of this thesis is to evaluate what effects high grouting pressures may have on the grouting process with respect to jacking. To obtain this, the theory is used to analyse data from a railway tunnel project in Norway, where considerably higher grouting pressures than in Sweden are used. The application of the theory has been successful, even though some minor adaptions have been necessary. The reason for the adaptions is that the RTGC-theory is developed for a more or less constant grouting pressure, while a varying pressure to some extent has been applied in the Norwegian project. The results suggest that using RTGC could save time and money by reducing grouting time and grout volume. The results also suggest that the high grouting pressures may cause considerable jacking if the geology and fracture situation is unfavourable. If and to what extent the jacking affects the final tightness of the rock mass has however not been possible to determine, given that data regarding measured leakage has not been available at the time for this analysis. It is shown that despite assumptions and simplifications in the geological model, using this theoretical approach enables the estimation of the effect that the grouting pressure has on the outcome of the performed grouting, arguably allowing for the optimum grouting pressure to be selected.

No description available.

As part of the Stockholm City Line project a grouting design was conducted and documentedduring the planning phase, based on theoretical grounds. This comprehensive design is the first of its kind for a tunneling project in Sweden. Due to the scale of the undertaking, the general design was ordered by the Swedish Transport Administration (Trafikverket) to apply for the pregrouting operations at the City Line’s rock tunnels. During the local design however, the grouting work developed differently within each sub-project from what was prescribed by the original design. This thesis project was carried out in cooperation with Trafikverket and concerns subjects related to the general grouting design for the City Line. The emphasis is on describing the general design, its theoretical background, and further to investigate what modifications were made during the local design. It was also to discuss the reasons and justifications for the changes at each sub-project. A detailed analysis of the grouting results at chosen sub-projects of the City Line has been performed, including: Vasatunnel & Odenplan Norrmalmstunnel Norrströmstunnel Södermalmstunnel The evaluation of results featured a calculation of sealing effects for the track tunnels at the different sites, which were then compared to the inflow requirements set by the Swedish Environmental Court. Further, a section of each sub-project was analyzed with respect to both pumping time and grout consumption. In total 96 pre-grouting fans, including approximately 2900 grouting holes were analyzed for this purpose. The goal was to identify the most economical method of grouting at the City Line, which still met all the demands regarding inleakage. The performed study showed that for all sub-projects the local grouting proceedings evolved considerably, although to varying extents, from the originally designed grouting concepts. In general the designed concepts were quite conservative, and not entirely applicable for grouting at large parts in its unchanged form. However they were hugely beneficial as excellent basis for local modifications made considering site specific conditions.Performed calculations showed that the grouting works at all the sub-projects provided sealing which fulfilled the requirements set by the Environmental court. However the pumping times and material consumption were different between all of them, which provided a basis for a discussion on how economical the grouting was at each site.If documenting of grouting methods and designs is carried on in future tunneling projects, especially of similar scale as the City Line, the knowledge gained can be transferred from one project to the next. Thus consistently building up further understanding on the complexities of hard rock grouting. / I anslutning till förprojekteringen av Citybanan-projektet i Stockholm genomfördes den första dokumenterade dimensioneringen av förinjektering för ett större tunnelprojekt i Sverige baserat på teoretiska grunder. Denna dimensionering beställdes av Trafikverket för att fungera som en utgångspunkt för förinjekteringen på Citybanans bergtunnlar. I samband med detaljprojekteringen och byggfasen av de olika delprojekten inom Citybanan, utvecklades förinjekteringen emellertid olika.Detta examensarbete genomfördes i samarbete med Trafikverket och behandlar frågeställningar relaterade till det injekteringskoncept som togs fram i samband med förprojekteringen.Tyngdpunkten ligger på att beskriva den ursprungliga dimensioneringen av förinjekteringen, dess teoretiska bakgrund samt vilka ändringar som genomfördes under detaljprojektering och byggfasen inom de olika delprojekten. Vidare diskuteras orsakerna och motiveringarna till de utförda förändringarna inom varje delprojekt. Därutöver genomfördes en detaljerad analys av resultaten från injekteringen vid de utvalda delprojekten inom Citybanan. Följande delprojekt ingick i analysen: Vasatunneln och Odenplan Norrmalmstunneln Norrströmstunneln Södermalmstunneln Utvärdering av resultaten innefattade en beräkning av tätningseffekterna för spårtunnlarna vid de olika delprojekten, vilka sedan jämfördes med tätningskraven som har fastställts av Miljödomstolen. Vidare analyserades en del av varje delprojekt med avseende på både pumptid och konsumtion av injekteringsbruk. Totalt analyserades 96 injekteringsskärmar som inkluderar cirka 2900 injekteringshål. Målet var att identifiera den mest ekonomiska metoden för injektering vid Citybanan som samtidigt uppfyller alla krav på inläckage.Den utförda studien visade att inom samtliga delprojekt vidareutvecklades det ursprungliga injekteringskonceptet i olika omfattning från det ursprungliga. Generellt var det ursprungligen utformade konceptet för förinjekteringen för konservativt och inte helt tillämplig för injektering på alla delar av Citybanan i oförändrad form. Men den utgjorde en bra bas för de lokala modifieringar som gjordes med avseende på platsspecifika förhållanden.Analysen av de utförda injekteringsarbetena visade att samtliga delprojekt uppfyllde de krav på tätning som fastställdes av Miljödomstolen. Pumptider och materialförbrukning mellan de olika delprojekten var emellertid starkt varierande. Resultaten från analysen utgjorde ett underlag för en diskussion om vilka injekteringsmetodiker vid de olika delprojekten som var mest kostnadseffektiva.Genom att dokumentera och analysera den dimensionering av injektering och injekteringsmetodik, såsom genomförts i detta examensarbete, i framtida större tunnelprojekt såsom Citybanan kan den erhållna kunskapen överföras från ett projekt till nästa. På så vis kan det konsekvent byggas upp en ökad förståelse och erfarenhet kring injektering i hårt berg.