Sub-grade soils of lateritic origin encountered in the construction of highway embankments in various regions of India, often comprise intrusions of soft lithomargic soils that result in large settlements during const...Sub-grade soils of lateritic origin encountered in the construction of highway embankments in various regions of India, often comprise intrusions of soft lithomargic soils that result in large settlements during constructions, and differential settlements at later stages. This necessitates the use of appropriate soil improvement techniques to improve the load-carrying capacity of pavements. This work deals with accelerated consolidation of un-reinforced and coir-rein- forced lateritic lithomargic soil blends, provided with three vertical sand drains. The load-settlement characteristics were studied for various preloads ranging from 50 kg (0.0013 N/mm2) to 500 kg (0.013N/mm2) on soil specimens prepared in circular ferro-cement moulds. It was observed that at lower preloads up to 200kg, across the blends, the relative increase in consolidation (Rct) for randomly reinforced soil with vertical drains was sig-nificantly higher than that of un-reinforced soil without vertical drains, with an average value of 124.8%. Also, the Rct for un-reinforced soil with vertical drains was quite higher than that of un-reinforced soil without vertical drains, with an average value of 103.9%. In the case of higher preloads, the Rct values for randomly reinforced soil with vertical drains were moderate with an average value of 30.88%, while the same for un-reinforced soil with vertical drains was about 20.4%. The aspect-ratio of coir fibers used was 1:275.展开更多
The behavior of sand drain was estimated so that the size of very large load-pressure could be eliminated by changing the configuration of the sand drain elements into sand wall.A 3D mathematical model was formulated ...The behavior of sand drain was estimated so that the size of very large load-pressure could be eliminated by changing the configuration of the sand drain elements into sand wall.A 3D mathematical model was formulated to transform the configuration of a sand drain into a sand wall to minimize or eliminate the excessive stress and primary settlement on the road base.This was barely considered in the past. According to soil mechanics theory and seepage characteristics of sand drain in road base foundations, a 3D sand drain element in FEM format was generated,and a matrix expression was formulated which was introduced into 3D Biot Consolidation展开更多
This paper presents the consolidation analysis of a foundation (Lianyungang City)with sand drain by vacuum priloading, and the calculation of excess pore pressure with anapproximate analytic method and displacement wi...This paper presents the consolidation analysis of a foundation (Lianyungang City)with sand drain by vacuum priloading, and the calculation of excess pore pressure with anapproximate analytic method and displacement with a numerical technique. This semi-analytical method takes in account the mutual effects of 3-dimensional consolidation, soilvisco-elasticity and sand drain group. The calculation is simple. The results have been checkedfairly well with field measurements.展开更多
文摘Sub-grade soils of lateritic origin encountered in the construction of highway embankments in various regions of India, often comprise intrusions of soft lithomargic soils that result in large settlements during constructions, and differential settlements at later stages. This necessitates the use of appropriate soil improvement techniques to improve the load-carrying capacity of pavements. This work deals with accelerated consolidation of un-reinforced and coir-rein- forced lateritic lithomargic soil blends, provided with three vertical sand drains. The load-settlement characteristics were studied for various preloads ranging from 50 kg (0.0013 N/mm2) to 500 kg (0.013N/mm2) on soil specimens prepared in circular ferro-cement moulds. It was observed that at lower preloads up to 200kg, across the blends, the relative increase in consolidation (Rct) for randomly reinforced soil with vertical drains was sig-nificantly higher than that of un-reinforced soil without vertical drains, with an average value of 124.8%. Also, the Rct for un-reinforced soil with vertical drains was quite higher than that of un-reinforced soil without vertical drains, with an average value of 103.9%. In the case of higher preloads, the Rct values for randomly reinforced soil with vertical drains were moderate with an average value of 30.88%, while the same for un-reinforced soil with vertical drains was about 20.4%. The aspect-ratio of coir fibers used was 1:275.
文摘The behavior of sand drain was estimated so that the size of very large load-pressure could be eliminated by changing the configuration of the sand drain elements into sand wall.A 3D mathematical model was formulated to transform the configuration of a sand drain into a sand wall to minimize or eliminate the excessive stress and primary settlement on the road base.This was barely considered in the past. According to soil mechanics theory and seepage characteristics of sand drain in road base foundations, a 3D sand drain element in FEM format was generated,and a matrix expression was formulated which was introduced into 3D Biot Consolidation
文摘This paper presents the consolidation analysis of a foundation (Lianyungang City)with sand drain by vacuum priloading, and the calculation of excess pore pressure with anapproximate analytic method and displacement with a numerical technique. This semi-analytical method takes in account the mutual effects of 3-dimensional consolidation, soilvisco-elasticity and sand drain group. The calculation is simple. The results have been checkedfairly well with field measurements.
