该文采用三维有限差分程序FLAC3D(Fast Lagrangian Analysis of Continua)对未加固和碎石桩加固的液化砂土地基进行数值模拟,对其建立模型以及进行地震响应分析,得到碎石桩加固液化地基土模型的抗液化效果。经数值分析,证实了碎石桩具...该文采用三维有限差分程序FLAC3D(Fast Lagrangian Analysis of Continua)对未加固和碎石桩加固的液化砂土地基进行数值模拟,对其建立模型以及进行地震响应分析,得到碎石桩加固液化地基土模型的抗液化效果。经数值分析,证实了碎石桩具有显著的排水效果。同时与振动台试验数据相比较,论证了数值模拟结果的可靠性。展开更多
该文运用三维有限差分软件FLAC3D(Fast Lagrangian Analysis of Continua)对水泥土桩加固的液化砂土地基建立模型并进行地震响应分析,从计算机数值模拟的角度对水泥土桩加固模型地基竖向位移、超静孔隙水压力、孔压比、剪应变增量、接...该文运用三维有限差分软件FLAC3D(Fast Lagrangian Analysis of Continua)对水泥土桩加固的液化砂土地基建立模型并进行地震响应分析,从计算机数值模拟的角度对水泥土桩加固模型地基竖向位移、超静孔隙水压力、孔压比、剪应变增量、接触面剪力及表面加速度作了较系统地分析,总结了这些参数的变化规律,得到了一些有价值的结论,对实际工程有一定的指导意义。展开更多
振冲碎石桩是目前工程中用于处理饱和砂土液化地基最有效、最经济、最普遍的方式之一,但是饱和砂土地基上碎石桩的抗震液化特性还有待于进一步研究。采用三维有限差分程序FLAC^(3D)(Fast Lagrangian Analysis of Continua)结合某地区燃...振冲碎石桩是目前工程中用于处理饱和砂土液化地基最有效、最经济、最普遍的方式之一,但是饱和砂土地基上碎石桩的抗震液化特性还有待于进一步研究。采用三维有限差分程序FLAC^(3D)(Fast Lagrangian Analysis of Continua)结合某地区燃气-蒸汽联合循环电站的饱和砂土类地基工程对碎石桩加固前后的砂土地基进行了数值模拟,对碎石桩施工前后两种不同工况建立模型并进行地震响应分析,通过对碎石桩加固前后两种工况下饱和砂土地基超静孔隙水压力与超孔压比的变化进行对比分析证实了碎石桩在3倍桩径范围内具有良好的排水效应与显著的抗液化特性,使得实际施工中所遇到的最大液化深度达到12.7m的问题得到有效解决,为类似工程提供了借鉴。通过对碎石桩加固前后两种工况下的孔隙水压力及渗流矢量进行对比分析,证实碎石桩可以在加固后的地基内形成一个有效的排水通道,且具有显著的抗液化能力。展开更多
Sand-gravel soil may not be suitable for structure use or excavation use as a result of their permeability and low-intensity.It may cause serious damage to the upper part of the structure for its considerable stress.H...Sand-gravel soil may not be suitable for structure use or excavation use as a result of their permeability and low-intensity.It may cause serious damage to the upper part of the structure for its considerable stress.How to assess and control the deformation of the ground is the main purpose of the soil reinforcement technology.Grouting is a method commonly used to meet those requirements.This study is designed to investigate the effects on shield construction in the sand-gravel stratum.展开更多
During the hydration process, the Ultra-fine Cements present specific physical and chemical characteristics; they are, very short setting time and high heat release. For special applications, such as rapid hardening a...During the hydration process, the Ultra-fine Cements present specific physical and chemical characteristics; they are, very short setting time and high heat release. For special applications, such as rapid hardening and early high strength mortars or concretes, these characteristics can be considered advantageous. Some commercial products used for concrete reinforcement and repairs are the Rapid Hardening Mortars, these mortars must develop a time of setting up to 3 h and an initial compressive strength of about 3.5 MPa once the hardening of the paste is reached. The objective of the present research work is to use Ultra-fine Cement for the preparation of a series of different Rapid Hardening Mortars （with different percentages of Ultra-fine Cement）, these mortars required the addition of a polycarboxylate-base specification F Superplasticizer. It was observed that the optimum water/cement （W/C） ratio for the hydration of the Ultra-fine Cements is W/C = 0.385. The Ultra-fine Cements were obtained by the High Energy Ball-milling technique at laboratory scale, 90% of the Particle Size Distribution is below 11 μm and the Blaine Specific Surface Area is over 9000 cm^2/g.展开更多
文摘该文采用三维有限差分程序FLAC3D(Fast Lagrangian Analysis of Continua)对未加固和碎石桩加固的液化砂土地基进行数值模拟,对其建立模型以及进行地震响应分析,得到碎石桩加固液化地基土模型的抗液化效果。经数值分析,证实了碎石桩具有显著的排水效果。同时与振动台试验数据相比较,论证了数值模拟结果的可靠性。
文摘该文运用三维有限差分软件FLAC3D(Fast Lagrangian Analysis of Continua)对水泥土桩加固的液化砂土地基建立模型并进行地震响应分析,从计算机数值模拟的角度对水泥土桩加固模型地基竖向位移、超静孔隙水压力、孔压比、剪应变增量、接触面剪力及表面加速度作了较系统地分析,总结了这些参数的变化规律,得到了一些有价值的结论,对实际工程有一定的指导意义。
文摘振冲碎石桩是目前工程中用于处理饱和砂土液化地基最有效、最经济、最普遍的方式之一,但是饱和砂土地基上碎石桩的抗震液化特性还有待于进一步研究。采用三维有限差分程序FLAC^(3D)(Fast Lagrangian Analysis of Continua)结合某地区燃气-蒸汽联合循环电站的饱和砂土类地基工程对碎石桩加固前后的砂土地基进行了数值模拟,对碎石桩施工前后两种不同工况建立模型并进行地震响应分析,通过对碎石桩加固前后两种工况下饱和砂土地基超静孔隙水压力与超孔压比的变化进行对比分析证实了碎石桩在3倍桩径范围内具有良好的排水效应与显著的抗液化特性,使得实际施工中所遇到的最大液化深度达到12.7m的问题得到有效解决,为类似工程提供了借鉴。通过对碎石桩加固前后两种工况下的孔隙水压力及渗流矢量进行对比分析,证实碎石桩可以在加固后的地基内形成一个有效的排水通道,且具有显著的抗液化能力。
文摘Sand-gravel soil may not be suitable for structure use or excavation use as a result of their permeability and low-intensity.It may cause serious damage to the upper part of the structure for its considerable stress.How to assess and control the deformation of the ground is the main purpose of the soil reinforcement technology.Grouting is a method commonly used to meet those requirements.This study is designed to investigate the effects on shield construction in the sand-gravel stratum.
文摘During the hydration process, the Ultra-fine Cements present specific physical and chemical characteristics; they are, very short setting time and high heat release. For special applications, such as rapid hardening and early high strength mortars or concretes, these characteristics can be considered advantageous. Some commercial products used for concrete reinforcement and repairs are the Rapid Hardening Mortars, these mortars must develop a time of setting up to 3 h and an initial compressive strength of about 3.5 MPa once the hardening of the paste is reached. The objective of the present research work is to use Ultra-fine Cement for the preparation of a series of different Rapid Hardening Mortars （with different percentages of Ultra-fine Cement）, these mortars required the addition of a polycarboxylate-base specification F Superplasticizer. It was observed that the optimum water/cement （W/C） ratio for the hydration of the Ultra-fine Cements is W/C = 0.385. The Ultra-fine Cements were obtained by the High Energy Ball-milling technique at laboratory scale, 90% of the Particle Size Distribution is below 11 μm and the Blaine Specific Surface Area is over 9000 cm^2/g.
