In tropical regions,heavy rainfall induces erosion and shallow landslides on road embankments.Cement-based stabilization methods,common in these regions,contribute to climate change due to their high carbon footprint....In tropical regions,heavy rainfall induces erosion and shallow landslides on road embankments.Cement-based stabilization methods,common in these regions,contribute to climate change due to their high carbon footprint.This study explored the potential application of coir fiber-reinforced laterite soil-bottom ash mixtures as embankment materials in the tropics.The objective is to enhance engineered embankment slopes'erosion resistance and stability while offering reuse options for industrial byproducts.This study examined various mix designs for unconfined compressive strength(UCS)and permeability,utilizing 30%bottom ash(BA)and 1%coir fiber(CF)with varying sizes ranging from 10 to 40 mm,6%lime,and laterite soil(LS),followed by microstructural analyses.The results demonstrate that the compressive strength increases as the CF length increases to 25 mm.In contrast,permeability increases continuously with increasing CF length.Lime-treated mixtures exhibit superior short-and long-term strength and reduce permeability owing to the formation of cementitious materials,as confirmed by microstructural analyses.A lab-scale slope box was constructed to evaluate the surface erosion of the stabilized laterite soil embankment.Based on the rainfall simulation results,the LS-BA-CF mixtures show better resistance to erosion and deformation compared to untreated LS,especially when lime is added to the top layer.This study provides insights into a sustainable and cost-effective approach for slope stabilization using BA and CF,offering a promising solution for tropical regions susceptible to surface erosion and landslides.展开更多
In nature there are situations where in foundation had to be placed over loose soil deposits. In such cases, deep foundations are recommended which increases cost of the structure. Black cotton soils, because of its h...In nature there are situations where in foundation had to be placed over loose soil deposits. In such cases, deep foundations are recommended which increases cost of the structure. Black cotton soils, because of its high swelling and shrinkage characteristics, have been a challenge to geotechnical engineers, increasing the strength of Clayey soil which is formed introducing randomly distributed fibers results in comparatively more homogeneous soil mixture and is one of the popular methods of soil stabilization. In the present study, model footing resting on BC soil reinforced with optimum percentage of treated and untreated coir fiber underlain by loose soil deposit was conducted to study its influence on bearing capacity and settlement. Loose soil deposit has been simulated by compacting sawdust in prefabricated steel tank. BC soil reinforced with optimum percentage of treated and untreated coir fibers has been compacted over loose sawdust and load settlement characteristics were determined at various D/B ratio of 1,2, 3 and for different sized model footings. The results indicated that settlement of model footings is significantly small at lower D/B = 1 and 2 ratios. Bearing capacity of BC soil is also found to be significantly affected by fiber reinforcement.展开更多
Soil exhibits layers of extreme compaction from both natural causes and wheel traffic.These compaction layers impede root growth,thereby reducing the plants capacity to obtain water during drought.Subsoil tillage is a...Soil exhibits layers of extreme compaction from both natural causes and wheel traffic.These compaction layers impede root growth,thereby reducing the plants capacity to obtain water during drought.Subsoil tillage is a remedy for adverse soil compaction that results in improved conditions for crop growth.Mechanical disturbance of subsoil increases water holding capacity and reduces impedance to root penetration.Vertical mulching is a technique that can be used to partially alleviate soil compaction within the critical root zones of deep rooted crops.A study was conducted by placing raw and composted coir pith using a two row subsoil coir pith mulching machine in three different soil depths(250,350,and 450 mm)at the three application rates of 15 t/ha,20 t/ha,and 25 t/ha and the effect of soil strength was investigated.The experiment was conducted for a rainfed cotton crop.The soil strength profile was recorded in all the treatments.The cone penetrometer resistance was measured for each increment of 10 mm and recorded manually from a digital force indicator during maturity stages of crop in all the treatment plots.The cone penetrometer resistance was measured directly on the row and the cone index was computed.Deep placement of mulch reduced the soil strength as compared to shallow placement.The lower soil strength(0.5 kPa to 0.8 kPa)in the loosened and mulched zone provided an impedance free zone for the root to proliferate.The rapid increase in cone index values at depths immediately below the respective depth of placement(250,350 and 450 mm)of raw and composted coir pith mulch indicated that the existence of undisturbed soil profile below the mulched zone which could be potential limiting factor for root development.展开更多
文摘In tropical regions,heavy rainfall induces erosion and shallow landslides on road embankments.Cement-based stabilization methods,common in these regions,contribute to climate change due to their high carbon footprint.This study explored the potential application of coir fiber-reinforced laterite soil-bottom ash mixtures as embankment materials in the tropics.The objective is to enhance engineered embankment slopes'erosion resistance and stability while offering reuse options for industrial byproducts.This study examined various mix designs for unconfined compressive strength(UCS)and permeability,utilizing 30%bottom ash(BA)and 1%coir fiber(CF)with varying sizes ranging from 10 to 40 mm,6%lime,and laterite soil(LS),followed by microstructural analyses.The results demonstrate that the compressive strength increases as the CF length increases to 25 mm.In contrast,permeability increases continuously with increasing CF length.Lime-treated mixtures exhibit superior short-and long-term strength and reduce permeability owing to the formation of cementitious materials,as confirmed by microstructural analyses.A lab-scale slope box was constructed to evaluate the surface erosion of the stabilized laterite soil embankment.Based on the rainfall simulation results,the LS-BA-CF mixtures show better resistance to erosion and deformation compared to untreated LS,especially when lime is added to the top layer.This study provides insights into a sustainable and cost-effective approach for slope stabilization using BA and CF,offering a promising solution for tropical regions susceptible to surface erosion and landslides.
文摘In nature there are situations where in foundation had to be placed over loose soil deposits. In such cases, deep foundations are recommended which increases cost of the structure. Black cotton soils, because of its high swelling and shrinkage characteristics, have been a challenge to geotechnical engineers, increasing the strength of Clayey soil which is formed introducing randomly distributed fibers results in comparatively more homogeneous soil mixture and is one of the popular methods of soil stabilization. In the present study, model footing resting on BC soil reinforced with optimum percentage of treated and untreated coir fiber underlain by loose soil deposit was conducted to study its influence on bearing capacity and settlement. Loose soil deposit has been simulated by compacting sawdust in prefabricated steel tank. BC soil reinforced with optimum percentage of treated and untreated coir fibers has been compacted over loose sawdust and load settlement characteristics were determined at various D/B ratio of 1,2, 3 and for different sized model footings. The results indicated that settlement of model footings is significantly small at lower D/B = 1 and 2 ratios. Bearing capacity of BC soil is also found to be significantly affected by fiber reinforcement.
文摘Soil exhibits layers of extreme compaction from both natural causes and wheel traffic.These compaction layers impede root growth,thereby reducing the plants capacity to obtain water during drought.Subsoil tillage is a remedy for adverse soil compaction that results in improved conditions for crop growth.Mechanical disturbance of subsoil increases water holding capacity and reduces impedance to root penetration.Vertical mulching is a technique that can be used to partially alleviate soil compaction within the critical root zones of deep rooted crops.A study was conducted by placing raw and composted coir pith using a two row subsoil coir pith mulching machine in three different soil depths(250,350,and 450 mm)at the three application rates of 15 t/ha,20 t/ha,and 25 t/ha and the effect of soil strength was investigated.The experiment was conducted for a rainfed cotton crop.The soil strength profile was recorded in all the treatments.The cone penetrometer resistance was measured for each increment of 10 mm and recorded manually from a digital force indicator during maturity stages of crop in all the treatment plots.The cone penetrometer resistance was measured directly on the row and the cone index was computed.Deep placement of mulch reduced the soil strength as compared to shallow placement.The lower soil strength(0.5 kPa to 0.8 kPa)in the loosened and mulched zone provided an impedance free zone for the root to proliferate.The rapid increase in cone index values at depths immediately below the respective depth of placement(250,350 and 450 mm)of raw and composted coir pith mulch indicated that the existence of undisturbed soil profile below the mulched zone which could be potential limiting factor for root development.
