Research On Grouts And Controllable Method Of Grouting In Rock Mass Of The Fissures

Grouting method in rock mass of the fissures is uncontrollable to a large extent now, shape and size of grouts consolidation is only determined indirectly and can hardly be forecasted accurately. This results in the great blindness of grouting practice. The effect and benefit of grouting depend on the techniques adjusted by the engineers. It is of theoretical and practical importance to study a kind of controllable grouting slurry for grouting time, to build theories of grouting spread considering many more factors and study a new type of controllable grouting method on the basis of these, in order to forecast spread scope of grouting slurry accurately, to fix shape and size of grouting, and that slurry can congeal within fixed time, decrease probability of underground water washing-out, increase setting strength, to raise the quality and benefit of grouting and change grouting from a "art"to "science", It can control quality of grouting from uncontrollable to controllable, reduce error that subjective factors cause, convert uncontrollable grouting method into controllable foundation dealing method. Nowadays, grouting slurry,grouting spread theory and grouting controlling method have defects to different extent. This text is aimed at these defects to study a new type of controllable slurry that is named by controllable composite slurry and provide reliable guarantee for grouting controllable method; to research spread law of Newtonian fluids and Bingham fluids and set up grouting spread model considering radius of underground water, to provide solid theoretical basement for grouting method, to set up mathematical model on the basis of grouting and spread theory and computerize it. My research mainly focuses on following aspects:(1) Based on the need of grouting method and defects of grouting slurry nowadays, to study a new kind of composite slurry that groutable period,initial and last setting can be controlled through experimental study, and to study parameters of viscosity,bleeding(stability),cohesion and setting strength etc. This discuss component property and test, and research all kinds of rheological parameters to provide reliable guarantee for grouting controllable method. (2)To research fissure parameters and summarize effects of many fissures parameters on grouting spread, to put forward frequent hydraulic aperture instead of equivalent hydraulic aperture and research influent law of Bingham fluids for basement of spread theory of Bingham fluids, to set up a single mass fissures model. (3)On the basis of influent law of Newtonian and Bingham fluids, to set up model of grouting spread of Newtonian fluids and Bingham fluids to provide theoretic basement for grouting method considering radius of underground water etc. and rheological parameters. (4)On the basis of previous research, to study a kind of controllable grouting method different from traditional grouting method and GIN grouting method and set up mathematical model, develop computer program. Grouts are classified by two kinds—fixed viscosity and changeable viscosity through study of time-varying of the grouts viscosity. Many chemical grouts for example acryamide and cement composite grouts is belong to fixed viscosity grouts, its characteristic is that viscosity is fixed before setting and increases rapidly after groutable period set fully at last. Changeable viscosity grouts increases viscosity gradually and. It accords with index law, promptly μ(t)=keat, t is mix time of grouts, k and a that are decided by properties of all kinds of grouts are unfixed constant, new concept of controllable composite grouts is putted forward on the basis of properties of ideal grouts. It researches function of accelerator and retardation in slurry and effect of them on groutable period, decide addition range of them on the basis of previous law and apply orthogonal experiment to develop a new kind of controllable cement-J85 accelerator-NH4H2PO4, in addition, find that NH4H2PO4 is the greatest effect factor on grouts, groutable period,initial and last setting time may be adjusted by addition of NH4H2PO4. Study parameters of viscosity,bleeding rate,stability,cohesion and setting strength, at the same time, compare all kinds of properties with bentonite stable grouts and concludes;(1) Controllable composite grouts have low initial viscosity and keep fixed viscosity and very good flowability and groutability before groutable period, as well range of viscosity may be adjusted greatly, phosphate has great effect on groutable period, formula of grouts may be adjusted according to factual need of engineering. (2) Based on development of viscosity of controllable composite grouts, viscosity of grouts increase rapidly and lose flowability after groutable period , time interval of groutable period,initial and last setting is short. This grouts belong to fixed viscosity and ensure that underground water can't wash out it more, it improve grouting effect and ensure grouting quality. This grouts is controllable, however, benetonite stable grouts is uncontrollable. (3) Controllable composite grouts belong to stable slurry, and its bleeding rate is smaller than 5%. (4) Cohesion of controllable grouts are low, its strong spreadability is benefit to spread and need small pressure. (5) Setting mass of this grouts have early high stage strength and good durability. (6) Controllable composite slurry can be applied in probing grouting,dam grouting,foundation engineering and ground dealing grout, it has low price and controllable property and prepare conveniently, it belongs to Bingham fluids of fixed viscosity. On the basis of current status of domestic andexternal grouts nowadays, this kind of controllable composite slurry is innovation of grouting slurry, it is in the lead in the field of domestic and external slurry, at the same time, it provides reliable guarantee for controllable method of grouting. Characteristic parameters of a single fissure comprises fissure aperture ,roughness,status of fissure area,tendency,coefficient of permeability,persistence,seepage, fissure aperture has more effect on grouting spread than roughness. A multi-fissure includes distribution,spacing and density. This text introduces methods of describing fissure aperture—machinery aperture,average aperture and equivalent hydraulic aperture, elaborate their defects, particularly equivalent hydraulic aperture hasn't factual value and is difficult to test in site, discuss superiority of frequency hydraulic aperture. It is high value that frequent hydraulic aperture instead of equivalent hydraulic aperture is applied in model of grouting spread, set up influent model of underground water of Bingham fluids considering existence and value of kernel to provide theoretical basis for model of Bingham fluid grouting spread, simultaneously build relationship between influent theory of underground water and theory of grouting spread, to create beneficial condition for deep study of grouting spread theory. It is theoretical innovation of influent law of underground water. Grouting spread model of Newtonian fluids and Bingham fluids is established considering factors of radius of underground water,frequent hydraulic aperture,time-varying law of viscosity,fissure dip angle and position angle and kernel etc on the basis of frequent hydraulic aperture and influent law of Bingham fluids research, and mathematical model is computerized to apply engineering conveniently, grouting spread theory is developed. This grouting spreading theory is contrasted and analyzed to reflect grouting spreading law, it approaches engineering actuality through engineering example. This model considers more factors, especially great and complex effect of geological factors on grouting spread, Value of fissure aperture is cleared and defined, all kinds of parameters of geology and grouts property in connection with model can be tested accurately, therefore this approach practice more and have more practical value comparing with other grouting model to provide solid theoretical basis for grouting controlling method. It is innovation in theory of grouting spreading. Based on previous controllable grouting slurry and new grouting spread model, fissure systems are classified three situations by different tendency, namely fissure system of unequal horizontal aperture; tilt fissure system of unequal aperture,dip angle and position angle; mix system of fissure of horizontal unequal aperture and tilt fissure system of unequal aperture,dip angle and position angle. Grout parameters are decided in accordance with three different situations: grouting time,grouting volume,grouting pressure and spread radius. Grouting pressure adopts domestic formula of low grouting pressure, relation between spreading radius and space ofhole is RL3calculated by pressure and spreading radius and previous spreading formula. Simultaneously, on the basis of it, mathematical model of new grouting controlling method is set up, controllable method of grouting construction technology and program is established, its mathematical model is computerized and developed program. With the help of it, all kinds of parameters can be adjusted at any time. It can decide grouting parameters rapidly and accurately in every situation. Controllable grouting method is putted forward on the basis of uncontrollable grouting method. The grouting method is controllable, this controllable method can control range and shape and quality of grouting and have high economic and social benefit. Project and establishment of new grouting method is significance of challenge. This text has established mathematical model and construction technology of grouting method and computerized it, at the same time, experimental work has been begin in construction site, initiative work has been done to set up an new kind of grouting method finally. This text all has creative points in the three fields of grouting slurry,grouting spreading theory and grouting method etc.(1) A kind of controllable composite grout is studied to solve nowadays defects of slurry and be strong basement of grouting controllable method, it is core of grouting controllable method in the field of slurry, it is qualitative leap of slurry;(2) Influent law of Bingham fluid is set up in the field of grouting theory, it simultaneously builds relationship between influent theory of underground water and theory of grouting spread to create beneficial condition for deep study of grouting spread theory. grouting spread model is set up considering radius of underground water,frequent hydraulic aperture and other geological factors and rheology of grouts, it is computerized. It is innovative to develop grouting spread theory. It provides scientific basis for establishment of grouting controllable method, it is theoretical basis for grouting controllable method; (3) Model of controllable grouting method is put forward and set up in the field of grouting method, it is computerized. It can control grouting time and volume and position and convert uncontrollable grouting into controllable grouting. Experimental work has been begun in construction site, initiative work has been done to set up an new kind of grouting method finally.