The aim of the present investigation is to improve the geotechnical properties of dispersive soil by reducing their dispersivity after elucidating the important mechanisms controlling the dispersivity of the soils. Dispersive soils have unique properties, which under certain conditions deflocculate and are rapidly eroded and carried away by water flow. These soils are found extensively in the United States, Australia, Greece, India, Latin America, South Africa and Thailand. The mechanism of dispersivity of soils is a subject matter of great interest for geotechnical engineers. In the earlier days clays were considered to be non erosive and highly resistant to water erosion. However, recently it was found that highly erosive clay soils do exist in nature. Apart from clayey soil, dispersivity is also observed in silty soils. The tendency of the clays to disperse or deflocculate depends upon the mineralogy and soil chemistry and also on the dissolved salts in the pore water and the eroding water. Such natural dispersive soils are problematic for geotechnical engineers. They are clayey soils which are highly susceptible to erosion in nature and contain a high percentage of exchangeable sodium ions, (Na+). It is considered that the soil dispersivity is mainly due to the presence of exchangeable sodium present in the structure. When dispersive clay soil is immersed in water, the clay fraction behaves like single-grained particles; that is, the clay particles have a minimum of electrochemical attraction and fail to closely adhere to, or bond with, other soil particles. This implies that the attractive forces are less than the repulsive forces thus leading to deflocculation (in saturated condition).This weakens the aggregates in the soil causing structural collapse. Such erosion may start in a drying crack, settlement crack, hydraulic fracture crack, or other channel of high permeability in a soil mass. Total failure of slopes in natural deposits is initiated by dispersion of clay particles along cracks, fissures and root holes, accelerated by seepage water. For dispersive clay soils to erode, a concentrated leakage channel such as a crack (even a very small crack) must exist through an earth embankment. Erosion of the walls of the channel then occurs along the entire length at the same time. Many slope and earth dam failures have occurred due to the presence of dispersive soils. Unlike erosion in cohesionless soils, erosion in dispersive clay is not a result of seepage through the pores of clay mass. However, the role of type of clay and its Cation exchange capacity in the dispersion of soil is not well understood. Data on the presence, properties, and tests for identification of dispersive clays is scarce. Hence, an attempt is made, in this thesis, to develop reliable methods to identify these soils and understand the extent of their dispersivity as well as to develop methods to control their dispersivity. The present study deals with the characterization of a local dispersive soil collected from southern part of Karnataka State. This study has focused on comprehensive tests to assess the dispersivity of the soils by different methods and to methods to improve geotechnical properties by reducing the dispersivity of the soil. An attempt is made to reduce the dispersivity of soil by using calcium based stabilizers such as lime, cement and fly ash. The mechanism of improvement in reducing the dispersivity of the soil with calcium based stabilizers has been studied. One of the important mechanism by which the dispersivity of the soil is reduced is by inducing cementation of soil particles. The differences in effectiveness of different additives are due to their differences in abilities to produce cementitious compounds. Although all the additives increased the strength of the soil and reduced the dispersivity of the soil, cement was found to significantly reduce the dispersivity of the soil, compared to the other two additives lime and fly ash. Cement is more effective as sufficient cementitious compounds are produced on hydration without depending on their formation. A detailed review of literature on all aspects connected with the present study is given in Chapter 2. A comprehensive description of dispersive soils present worldwide has been brought out in this section. Based on this survey, the scope of the present investigation has been elaborated at the end of the chapter. To understand the reasons for dispersivity of the soil and to estimate its degree of dispersivity, it is essential to assess standard methods to characterize the soil. Chapter 3 presents a summary of material properties and testing programs. The results of geotechnical characterization of the soil, the index properties of the soilspecific gravity, sieve analysis, Atterberg’s limits are discussed in Chapter 4. The physico chemical characteristics play an important role in determining the amount of dispersivity of the soil. Dispersive soils have two main characteristics which define its dispersivity chemically. These are Sodium Adsorption Ratio (S.A.R) and Exchangeable Sodium Percentage (E.S.P). The two characteristics are determined from the Cation exchange capacity of the soil. Exchangeable Sodium Percentage is defined as the concentration of sodium ions present in the soil with respect to the Cat ion exchange capacity of the soil. And Sodium Adsorption Ratio is used to quantify the free salts present in the pore water. Since Atterberg’s limits and grain size analysis do not help in identifying dispersive soils or in quantifying its dispersivity, two other tests- Emerson Crumb test and double hydrometer test were carried out on the soil. Emerson crumb test is a simple way for identification of dispersive soils. In this test, a crumb of soil measuring about 1mm diameter is immersed in a beaker containing distilled water and the subsequent reaction is observed for 5 minutes. It is solely based on direct qualitative observations. Depending on the degree of turbidity of the cloud formed in the beaker, the soil is classified in one of the four levels of dispersion in accordance with ASTM-D6572. Since this test is mainly a qualitative test and does not help in quantifying the dispersivity, it cannot be depended upon completely in identifying a dispersive soil. Another test double hydrometer test, which helps in quantifying the dispersivity of the soil, was also conducted on the soil. This test involves in conducting the particle size distribution using the standard hydrometer test in which the soil specimen was dispersed in distilled water with a chemical dispersant. A parallel hydrometer test was conducted on another soil specimen, but without a chemical dispersant. The dispersing agent used for the experiment was sodium hexametaphosphate. The percent dispersion is the ratio of the dry mass of particles smaller than 0.005 mm diameter of the test without dispersing agent to the test with dispersing agent expressed as a percentage. The double hydrometer test was carried out according to Double Hydrometer Test (ASTM D4221). Apart from the conventional tests, attempts are made to consider shrinkage limit test and unconfined compression test to determine the dispersivity of the soil. For this purpose, the shrinkage limit of the soil was determined with and without dispersing agent. The initial shrinkage limit of the untreated soil reduced on treating it with dispersing agent, thus indicating that the soil had further dispersed on addition of dispersing agent. In order to carry out the unconfined compression strength, the maximum dry density and optimum moisture content was determined through the compaction test. The soil was then treated with dispersing agent and compacted at the optimum moisture content. The soil exhibited high degree of dispersion through the strength test. Hence it is necessary to stabilize the soil with additives. Detailed experimental program has been drawn to find methods to improve the geotechnical properties and to reduce the dispersivity of the soil. Chapter 5 presents the investigations carried out on the dispersive soil with lime. The importance of lime stabilization and the mechanism of lime stabilization have been discussed initially. Commercially obtained hydrated lime was used in the present study. The soil was treated with three different percentages of lime 3, 5 and 8. The curing period was varied from one day to twenty eight days. The effect of addition of lime on various properties of the soil such as pH, Atterberg’s limits, compaction test and unconfined compression test is elaborated in chapter 5. The pH of the soil was maximum on addition of 3% lime. On further addition, the pH decreased and remained constant. The liquid limit of the soil increased on adding 3% lime and decreased with further lime content. The compaction test conducted on the soil showed an increase in maximum dry density of the soil and reduction in optimum moisture content with 3% lime content. On further increase in the lime content, the soil showed a decrease in the maximum dry density and increase in optimum moisture content. The unconfined compressive strength of the soil also increased on increasing lime content upto 5%. The variation in strength of the soil with respect to curing period was also compared. Optimum lime content arrived at based on the above conducted tests was 3%. The effect of lime in reducing the dispersivity of the soil through shrinkage limit test and unconfined compression test is also presented in this chapter. Details of the efforts made on the soil with fly ash are presented in Chapter 6.The fly ash used for stabilization of Suddha soil was of Class F type. This type of fly ash contains low reactive silica and lime. The effect of varying fly ash content on the properties of Suddha soil by varying the percentage of fly ash from 3 to 10 percentages is discussed in this chapter. The tests conducted on fly ash treated Suddha soil were pH test, compaction test, Atterberg’s limits and unconfined compression test with varying curing period. The fly ash treated Suddha soil was cured from one day to twenty eight days for the unconfined compressive strength analysis. The pH of the soil system increased with increasing percentage of fly ash. The increase in liquid limit was marginal on addition of fly ash. The maximum dry density of fly ash treated Suddha soil decreased continuously and the optimum moisture content of the treated soil increased with increasing fly ash content. The unconfined compressive strength of Suddha soil increased with increase in fly ash content upto 8% and then decreased for fly ash content of 10%. For all the percentages of fly ash added, the strength of the soil increased with increase in the curing period. The effect of fly ash in reducing the dispersivity of the soil was carried out using shrinkage limit and unconfined compression test. It was seen that on increasing the fly ash content, the soil treated with dispersing agent showed an increase in the shrinkage limit. Also, the same trend was observed for the unconfined compression strength to determine dispersivity. Optimum fly ash was determined as 8% with the help of all the tests conducted on the soil. Since the improvement in the properties of the soil with lime and fly ash was not very high, Cement was also considered as another additive used for stabilization of Suddha soil. It is known that soil with lesser amount of clay content will respond well with cement. The effect of cement addition on various properties of Suddha soil has been brought out in Chapter 7. It was found that addition of cement had positive effects on all the properties of Suddha soil. The pH of the soil increased for all the percentages of cement addition. The liquid limit of the soil increased on increasing the cement content. The shrinkage limit also showed a similar trend. The optimum moisture content of the soil decreased on increasing the cement content for Suddha soil and the maximum dry density increased for cement treated Suddha soil. The soil showed the maximum dry density at 8% cement content. The unconfined compression strength conducted on cement treated Suddha soil increased significantly for higher cement contents and also with curing period. Suddha soil when treated with 8% cement content exhibited maximum strength in comparison to other percentages. Also, the effect of cement in reducing the dispersivity of the soil was carried out using shrinkage limit and unconfined compression test. The shrinkage limit of the soil increased for all percentages of cement content, even in the presence of dispersing agent. Through the unconfined compression strength for dispersivity, it could be seen that 8% cement treated Suddha soil had the least dispersion. Optimum cement content was derived as 8% with the help of the tests conducted on the soil. A comparison of effect of all the additives on the strength of the soil as well as effect of the additives in reducing the dispersivity of the soil is discussed in Chapter 8. The effect of additives on the shrinkage limit of the soil with and without dispersing agent has been compared. The variation in shrinkage limit of the soil when treated with the additives was due to the different mechanisms involved in reducing the dispersivity by each additive. The effect on the unconfined compression strength of the soil treated with the additives with and without dispersing agent is also brought out in this chapter. It was noted that the dispersion exhibited through shrinkage limit test was lesser as compared to the percentage dispersivity exhibited through unconfined compression test. Hence it could be said that dispersion of the soil is due to loss of cohesion than volume change behavior. Also, the unconfined compression strength of the soils with respect to curing period is compared. The percentage dispersivity calculated through these tests is summarized and compared. With the help of this it could be said that to control the dispersivity of the soil, it is necessary to enhance the strength of the soil. The general summary and major conclusions drawn from the thesis are presented in Chapter 9.

Control of groundwater plays an important part in operations at many open pit mines. Selection of an efficient and cost effective dewatering program that will improve slope stability of the pit walls is frequently complicated by the complex and somewhat uncertain hydrogeologic environment found at most mine sites. This dissertation describes a risk-cost-benefit (RCB) framework that can be used to identify the most effective dewatering strategy under such conditions, because the stochastic framework explicitly accounts for uncertainty in hydrogeologic and shear strength parameters in the groundwater flow, slope stability and economic analyses. In the framework, the monetary worth of each design alternative is measured in terms of an economic objective function. This function is defined in terms of a discounted stream of benefits, costs and risks over the operational life of the mine. Benefits consist of revenue generated from the sale of mineral concentrate. Costs include normal operating and dewatering expenses. Monetary risks are defined as the economic consequences associated with slope failure of the pit wall, multiplied by the probability of such a failure occurring. Selection of the best design strategy from a specified set of alternatives is achieved by determining the economic objective function for each design and then selecting the alternative that yields the highest value of the objective function. Estimation of the probability of slope failure requires an accurate assessment of the level of uncertainty associated with each input parameter, a forecast of how dewatering efforts are expected to affect pore pressures in the pit wall in light of the uncertain hydrogeologic environment, and an evaluation of the effect that the pore pressure reductions will have on improving stability of the pit wall. Prediction of the pore pressure response to dewatering efforts is achieved with SG-FLOW, a steady state, saturated-unsaturated finite element model of groundwater flow. Slope stability is evaluated with SG-SLOPE, a two dimensional, limit equilibrium stability model based on the versatile Sarma method of stability analysis. To account for input parameter uncertainty, both the groundwater flow stability models are invoked in a conditional Monte-Carlo simulation that is based on a geostatistical description of the level of uncertainty inherent in the available hydrogeological and geotechnical data. Besides documenting the methodology implemented in the framework to conduct the geostatistical groundwater flow and economic analyses of the objective function, this dissertation also presents a sensitivity analysis and a case history study that demonstrate the application of the RCB framework to design problems typically encountered in operating mines. The sensitivity study explores how each set of input parameters, including hydrologic data, shear strength parameters, slope angles of the pit wall and dewatering system specifications impact on the profitability of the mining operation. The study utilized a base case scenario that is based on overburden conditions at Highland Valley Copper; therefore, the conclusions cannot be applied blindly at other sites. However, the framework can be used to formulate site specific conclusions for other large base-metal open pit mines. After the objective function was calculated for the base case, the aforementioned input parameters were systematically perturbed in turn to study how each parameter impacts on profitability of the mine. The sensitivity study showed that in the particular case analyzed changes in the slope angle and dewatering efforts can improve profitability by many millions of dollars. In particular, steep slope angles can be utilized in the early stages of mine development while the pit walls are relatively low, and then flattened as the pit wall height increases and the monetary consequences of slope failure become more pronounced. Furthermore, the sensitivity results indicated that pit dewatering is likely to be effective over a range of hydraulic conductivities from lxlO"8 m/s to lxlO'5 m/s and that accurate estimation of the mean hydraulic conductivity is much more important than estimating other statistics that describe the hydraulic conductivity field, including the variance and the range of correlation. Results of the sensitivity study clearly demonstrate that the RCB framework can be used effectively to identify the most effective dewatering strategy given a limited amount of geologic and hydrologic information. Also, it is shown that the framework can be used to identify the most important input parameters for each specific dewatering problem and to establish the approximate monetary worth of data collection. The case history study documents how the RCB framework was applied at Highland Valley Copper (HVC). Groundwater control is recognized as an important component of mining operations at this mine site; dewatering measures utilized on the property involve both high capacity dewatering wells and horizontal drains. The benefits of pit dewatering include improved slope stability, drier operating conditions in the pit, and a convenient production water supply. These benefits do not come cheaply, HVC is expecting to spend in excess of six million dollars on groundwater control in the next ten years. Before investing such large sums in groundwater control, mine management should be confident that the capital investment is justified, i.e. that the resulting economic benefits will significantly exceed the costs of the dewatering effort. Using historical data provided by HVC, the case history study documented in this dissertation shows how the RCB framework is used to identify the most profitable combination of slope geometry and groundwater control in design sector R3 of HVC's Valley Pit. By considering three possible slope angle and groundwater control options it is shown that by continuing to implement an aggressive dewatering program, HVC can expect to reduce operating costs by as much as nine million dollars in this design sector. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

the mail goal is to explore a procedure of seizing working station "Exportní prodejce" and a the process of long stabilization of the new workers in this working station in the company Velteko,s.r.o, identify eventually absences and try to project solution and the ideal procedure of obtaining, selection, adaptation and stabilization workers on the working station "Exportní prodejce".

M.Tech. / There is a general lack of understanding of the laboratory compaction test based on the vibrating hammer method. The impact method of testing soil in the laboratory is conservatively used by engineers for design and construction control purposes even when the specified mode of compaction on site is vibratory. Furthermore, the effects of vibratory compaction are not fully understood, and hence this mode of compaction in the field has not always been effectively utilized. The objective of this research project was to determine whether the vibrating hammer method could be used in the laboratory for design and control purposes, through an investigation of its operating characteristics, and a comparison of its effectiveness against that of the impact method, following a study of the compaction properties of a range of different soils used in road and embankment construction. The results of the study showed that the vibrating hammer can be used in place of impact in the laboratory for non-cohesive soils and gravels. In one instance, vibratory compaction produced maximum dry densities for a decomposed granite which were almost 5 % higher than that for impact compaction. Cohesive soils reached maximum compaction at moisture contents which were 7 % wetter under the vibratory mode as opposed to those for impact, but at lower densities. This showed that field densities under vibratory compaction would be difficult to achieve when the laboratory control method was based on impact. The research showed that electrical power input to the vibrating hammer must be carefully regulated in order to maintain specified standards which are based on a fixed frequency. Further study based on operation at different frequencies would be required to determine whether the vibrating hammer would be suitable for cohesive soils having natural frequencies lower than the current standard specified.

Title: Analysis of postural reactions of excercise with a load of upper limbs by centrifugal force. Summary: The aim of the study is the kinematic analysis of selected body segments (C7, Th4, Th8, Th12, AC and SIPS) during performance with a special exercise tool Marrko Core®. Another goal is to confirm the existing knowledge in the field of kinesiology about the rotation of spinal segments. In addition, we aim to compare the selected exercises with each other and asses their suitability for application in the general population with back pain of various etiologies. The experiment was performed as a biomechanical study, where specific biomechanical parameters in human body kinetics and muscle activity were measured during performance of specific exercises. All measurements have been undertaken in laboratory BEZ UK FTVS. Systems Qualisys, Kistler and EMG Noraxon were used for measurements of chosen parameters in human body kinetics and muscle activity. Participants: Participants attended in this study (8 individuals- 4 women and 4 men) were all healthy individuals, 20-40 years old, without any limitation of mobility and pain free. They were all recreational athletes. Key words: EMG, Kistler, Qualisys, postural stabilizatio

A thesis submitted to the Faculty of Engineering and Built Environment, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the Degree of Doctor of Philosophy, 2017 / The effect of internal erosion on the mechanical behaviour of soils was investigated experimentally, using sodium chloride grains as an analogue for erodible soil grains. With this technique, the loss of controlled quantities of finer particles could be simulated under more realistic hydro-mechanical conditions than in previous research, but within practical experimental time scales. Two experimental programs were undertaken. The first looked at general changes in volume and shear strength using a large diameter oedometer adapted to perform a punch test following salt dissolution. The second program investigated particular changes in volume and shear strength following salt dissolution using an adapted direct shear box Previous studies have shown shear strength reductions following the loss of finer particles representing as little as 5 % of the total mass of the original soil. Findings here show shear strength can be largely unaffected if the erodible finer fraction (F) makes up less than a transition value (Ft) of approximately 10 – 15 % by mass of the original soil. This threshold represents F above which the coarser fabric is looser than at its minimum void ratio. As F increases further, finer particles increasingly hinder the coarser particles from achieving their densest packing, such that the coarser fabric remaining after finer particle loss is in a looser state than the original fabric, the remaining fabric reaching its maximum void ratio at a critical finer fraction (Fc) of approximately 25 – 35 %. For F < Fc, finer particle loss results in limited collapse of the coarser fabric and it was found that the state of this initial coarser fabric determines the shear behaviour of the soil following the loss of finer particles. The shear behaviour of initially dense specimens with F < Ft remained similar to that of a dense soil following finer particle loss, whereas shear behaviour of initially dense specimens with Ft < F < Fc approached that of a loose soil as F increased. Soils with higher internal filter ratios (D15c/D85f) were found to have higher values of Ft and Fc. Soils with F > Fc, settled and weakened significantly following finer particle loss, reflecting the load-bearing role finer particles play in this case. This load bearing nature of the finer particles in soils with F > Fc decreases the risk of internal erosion. / CK2018

As computing power becomes more and more available, robotic systems are moving away from active sensors for environmental awareness and transitioning into passive vision sensors.  With the advent of teleoperation and real-time video tracking of dynamic environments, the need to stabilize video onboard mobile robots has become more prevalent. This thesis presents a digital stabilization method that incorporates inertial fusion with a Kalman filter.  The camera motion is derived visually by tracking SIFT features in the video feed and fitting them to an affine model.  The digital motion is fused with a 3 axis rotational motion measured by an inertial measurement unit (IMU) rigidly attached to the camera. The video is stabilized by digitally manipulating the image plane opposite of the unwanted motion. The result is the foundation of a robust video stabilizer comprised of both visual and inertial measurements.  The stabilizer is immune to dynamic scenes and requires less computation than current digital video stabilization methods. / Master of Science

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