Shallow foundations rested on Leda clay that are widely distributed in Eastern Canada exhibit shrinkage characteristics and are prone to differential settlements. Due to this reason, significant repairs are necessary to the foundations and basements of residential structures constructed in Leda clay deposits. Differential settlements are commonly attributed to the changes in the natural water content of soils associated with water infiltration, evaporation or plant transpiration (i.e., tree-roots-suction). Various research studies have been undertaken to estimate the possible settlements of shallow foundations associated with the water infiltration or evaporation. Several thumb rules have been proposed through research studies, providing recommendations with respect to the distance at which trees must be planted as a function of their heights at maturity such that differential settlements can be avoided. However, limited studies have been carried out to estimate or model the settlements of shallow foundations taking into account the influence of tree-roots-suction. In the present research program, a comprehensive experimental study regarding the deformation characteristics of a sandy loam soil from Ottawa due to tree-root-suction is undertaken, using specially designed equipment. The study has been undertaken using a sandy loam soil so that the testing program can be conducted in a shorter period of time. An artificial rooting system (ARS) was designed and placed in a specially designed tank at the University of Ottawa to simulate tree-roots-suction and measure soil surface settlements associated with a decrease in natural water content (or increase in soil suction) using particle image velocimetry (PIV) technique. The ARS consists of an artificial root, suction generator, matric suction and volumetric water content monitoring devices. The variation of matric suction and volumetric water content are monitored at various depths using the instrumentation of the ARS. Based on the results of the experimental studies, a methodology is proposed to model the settlement behaviour of sandy loam soils due to suction from ARS, using commercial finite element software, SEEP/W and SIGMA/W (i.e. software package of GeoStudio 2007). The study offers a reasonably good comparison between the measured surface settlements and those estimated using the finite element modelling analysis. The modelling methodology presented in this thesis is promising and may be extended for estimating the settlement behaviour associated with the tree roots suction of Leda clay deposits and to other soils.

Shallow foundations rested on Leda clay that are widely distributed in Eastern Canada exhibit shrinkage characteristics and are prone to differential settlements. Due to this reason, significant repairs are necessary to the foundations and basements of residential structures constructed in Leda clay deposits. Differential settlements are commonly attributed to the changes in the natural water content of soils associated with water infiltration, evaporation or plant transpiration (i.e., tree-roots-suction). Various research studies have been undertaken to estimate the possible settlements of shallow foundations associated with the water infiltration or evaporation. Several thumb rules have been proposed through research studies, providing recommendations with respect to the distance at which trees must be planted as a function of their heights at maturity such that differential settlements can be avoided. However, limited studies have been carried out to estimate or model the settlements of shallow foundations taking into account the influence of tree-roots-suction. In the present research program, a comprehensive experimental study regarding the deformation characteristics of a sandy loam soil from Ottawa due to tree-root-suction is undertaken, using specially designed equipment. The study has been undertaken using a sandy loam soil so that the testing program can be conducted in a shorter period of time. An artificial rooting system (ARS) was designed and placed in a specially designed tank at the University of Ottawa to simulate tree-roots-suction and measure soil surface settlements associated with a decrease in natural water content (or increase in soil suction) using particle image velocimetry (PIV) technique. The ARS consists of an artificial root, suction generator, matric suction and volumetric water content monitoring devices. The variation of matric suction and volumetric water content are monitored at various depths using the instrumentation of the ARS. Based on the results of the experimental studies, a methodology is proposed to model the settlement behaviour of sandy loam soils due to suction from ARS, using commercial finite element software, SEEP/W and SIGMA/W (i.e. software package of GeoStudio 2007). The study offers a reasonably good comparison between the measured surface settlements and those estimated using the finite element modelling analysis. The modelling methodology presented in this thesis is promising and may be extended for estimating the settlement behaviour associated with the tree roots suction of Leda clay deposits and to other soils.

Magistro darbe tiriama kadmio ir švino adsorbcijos ir desorbcijos procesai bei jų tarpusavio sąveika skirtingos granuliometrinės sudėties dirvožemiuose. Darbo objektas - du skirtingos granuliometrinės sudėties (priesmėlio ir priemolio) dirvožemiai. Darbo tikslas – ištirti kadmio ir švino adsorbcijos-desorbcijos procesus ir jų tarpusavio sąveikos poveikį jų judrumui tiriamuose dirvožemiuose. Darbo metodai – švino, kadmio, ir jų mišinių adsorbcijos dirvožemiuose procesui tirti dirvožemių ėminiai iki pusiausvyrosios būsenos buvo plakami su skirtingos koncentracijos (0, 0,25, 0,5, 1 mM) Cd (NO3)2, Pb(NO3)2 ir jų mišinių tirpalais, paruoštais 0,03M NaNO3 tirpale pastoviai joninei jėgai palaikyti. Po adsorbcijos eksperimento Cd2+ ir Pb2+ jonų koncentracijos pusiausvirajame tirpale nustatytos liepsnos atominės absorbcinės spektrometrijos metodu (AAS). Desorbcijos procesas ištirtas tuose pačiuose mėginiuose panaudojant ekstrakciją su 0,05M NH4 – EDTA (pH 7) ekstrahentu. Ekstraktuose Pb2+ ir Cd2+ jonų koncentracijos nustatytos liepsnos AAS metodu. Tyrimo rezultatai įvertinti matematiniais-statistiniais metodais naudojant Excel programą. Darbo rezultatai. Atlikus tyrimus nustatyta kad priesmėlio dirvožemis adsorbuoja (esant 1 mM (207 mg•kg-1) koncentracijai) 206,2 mg•kg-1 Pb, 109,9 mg•kg-1 Cd sausosios masės, o desorbuoja 97,7 mg•kg-1 Pb ir 61,6 mg•kg-1 Cd sausosios masės. O priemolio dirvožemis adsorbuoja esant tai pačiai koncentracijai 206,6 mg•kg-1 Pb ir 107,3 mg•kg-1 Cd s.m... [toliau žr. visą tekstą] / In this master work was investigated cadmium and lead adsorption – desorbtion processes and their interaction impact on thier imobility in soils of different texture. Work subject - two soils of different texture (loam and sandy loam). Work objective – to investigate cadmium and lead adsorption – desorbtion processes and their interaction impact on thier imobility in soils of different texture. Work methods – the investigated soil samples were agitated with Cd (NO3)2, Pb(NO3)2 solutions of different concentrations (0, 0,25, 0,5, 1 mM) as well as with solutions of thier mixtures. The solutions were prepared in the 0,03 M NaNO3 for the maintaining of constant ionic strength. After adsoption experiment, the Cd2+ and Pb2+ ionic concentrations in the equilibrium solution were determined with atomic adsorption spectrometer (AAS). The desorption was investigated in the same samples using 0,05M NH4 – EDTA (pH 7) extractant. In extracts Pb2+ and Cd2+ ionics concentrations were determinadet with AAS. Work results – after investigation observed that sandy soil absorbed 109,9 mg•kg-1 Cd and 206,2 mg•kg-1 Pb, desorbed 61,6 mg•kg-1 Cd and 97,7 mg•kg-1 Pb. And loam soil absorbed 107,3 mg•kg-1 Cd and 206,6 mg•kg-1 Pb, desorbed 57,1 mg•kg-1 Cd and 82,4 mg•kg-1 Pb. Cd in loam soil after Pb adsorption and desorption in Cd-Pb model-sistem the influence was tenuous, while the dorsorption decreased only in loam soil and only in the low concentations (unto 0,5 mM Cd-Pb). Keywords:... [to full text]

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Shallow foundations rested on Leda clay that are widely distributed in Eastern Canada exhibit shrinkage characteristics and are prone to differential settlements. Due to this reason, significant repairs are necessary to the foundations and basements of residential structures constructed in Leda clay deposits. Differential settlements are commonly attributed to the changes in the natural water content of soils associated with water infiltration, evaporation or plant transpiration (i.e., tree-roots-suction). Various research studies have been undertaken to estimate the possible settlements of shallow foundations associated with the water infiltration or evaporation. Several thumb rules have been proposed through research studies, providing recommendations with respect to the distance at which trees must be planted as a function of their heights at maturity such that differential settlements can be avoided. However, limited studies have been carried out to estimate or model the settlements of shallow foundations taking into account the influence of tree-roots-suction. In the present research program, a comprehensive experimental study regarding the deformation characteristics of a sandy loam soil from Ottawa due to tree-root-suction is undertaken, using specially designed equipment. The study has been undertaken using a sandy loam soil so that the testing program can be conducted in a shorter period of time. An artificial rooting system (ARS) was designed and placed in a specially designed tank at the University of Ottawa to simulate tree-roots-suction and measure soil surface settlements associated with a decrease in natural water content (or increase in soil suction) using particle image velocimetry (PIV) technique. The ARS consists of an artificial root, suction generator, matric suction and volumetric water content monitoring devices. The variation of matric suction and volumetric water content are monitored at various depths using the instrumentation of the ARS. Based on the results of the experimental studies, a methodology is proposed to model the settlement behaviour of sandy loam soils due to suction from ARS, using commercial finite element software, SEEP/W and SIGMA/W (i.e. software package of GeoStudio 2007). The study offers a reasonably good comparison between the measured surface settlements and those estimated using the finite element modelling analysis. The modelling methodology presented in this thesis is promising and may be extended for estimating the settlement behaviour associated with the tree roots suction of Leda clay deposits and to other soils.

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During 1967-68 experiments to determine the comparative effect of various nitrogenous fertilizers on soil reaction and soil aggregation of the Fox sandy loam, the Lincoln loam and the Lincoln clay loam were carried out in the pedology Laboratory of the Department of Geography, McMaster University. The soil samples were taken from the Horticultural Experiment Station, Simcoe, Ontario. A review of literature is presented in Chapter II. Chapter III discusses experimental techniques, results and a discussion of problems encountered. Chapter IV summarizes the results of the survey and analyses. / Thesis / Master of Arts (MA)

Thesis (M.Sc. Agriculture. (Soil Science)) -- University of Limpopo, 2022 / The constant growth experienced by the coffee industry has led to the high-volume production of coffee waste worldwide. One of the main coffee wastes is spent coffee ground (SCG), a residue obtained after the ground coffee beans are treated under pressure. The present study was aimed to investigate the utilization of SCG to amend soil physicochemical properties. This study was conducted at Greenhouse Biotechnologies Research Centre of Excellence, University of Limpopo, South Africa, where the effect of various rates of SCG concentration in volume percentage (vol%) was tested for a period of nine months. The spent coffee ground residue was collected from four restaurants at Haenertsburg, and the application rates were 0, 5, 10, 20, 30, 50 vol%. To evaluate the change in soil physicochemical properties overtime, the incubation period was divided into four test periods namely T1 was after a month, T3 after 3 months, T6 after 6 months, and T9 after 9 months. Physicochemical properties including nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg), calcium (Ca), total organic carbon (TOC), cadmium (Cd), copper (Cu), nickel (Ni), zinc (Zn), and lead (Pb), pH, electrical conductivity (EC), C:N ratio, large macroaggregates (LM), small macroaggregates (sM), microaggregates (m), unaggregated silt and clay (s+c), mean weight diameter (MWD) and soil moisture content (SMC) were quantified at the end of each test period. Results revealed that the interaction between incubation periods and various SCG application rates significantly (p<0.05) increased pHw, EC, MWD, LM, base cations and significantly decreased TOC, heavy metals, SMC, m, and sM. Spent coffee ground increased pHw and EC of the soil at all application rates and reached a maximum of 7.8 units at T6 in treatment SCG-5 and 202.30 S/cm at T9 in treatment SCG-50 above the control respectively. Total organic carbon increased by 548% above control in the highest treatment (SCG-50) at T1, but, however, started declining from T3 in all treatments across the incubation period. SCG’s highest application rates (SCG-20 to SCG-50) reduced the soil Cd toxicity (threshold of >2 mg/kg), but however, also reduced the availability of micronutrients (Cu and Zn) during the incubation period. At T9, Mg, Ca, K, and P increased from mean values of 55.9 to 77.9, 40.9 to 62.2, 77.4 to 112, and 22.0 to 30.0 mg/Kg above control in treatments with high application rates. LM increased whilst sM, and m decreased across the incubation period in all treatments. MWD increased by 46% at T1 and reached its maximum of 56% at T6 in treatment SCG-50 above control. Additionally, there was a positive relationship between LM and MWD. Soil moisture content however increased to 60.26% at T1 in treatment SCG-50 and decreased from T3 across the incubation period. Spent coffee ground has the potential to be used as a liming material, a chelating agent, and for water management in semi-arid areas. It retains and cycles nutrients and improves soil structure through aggregation. However, research should be done in field conditions to access the effectiveness of this residue. / NRF