This paper introduces a slurry suspension settlement prediction model for cohesive sediment in a still water environment. With no sediment input and a still water environment condition, control forces between settling...This paper introduces a slurry suspension settlement prediction model for cohesive sediment in a still water environment. With no sediment input and a still water environment condition, control forces between settling particles are significantly different in the process of sedimentation rate attenuation, and the settlement process includes the free sedimentation stage, the log-linear attenuation stage, and the stable consolidation stage according to sedimentation rate attenuation. Settlement equations for sedimentation height and time were established based on sedimentation rate attenuation properties of different sedimentation stages. Finally, a slurry suspension settlement prediction model based on slurry parameters was set up with a foundation being that the model parameters were determined by the basic parameters of slurry. The results of the settlement prediction model show good agreement with those of the settlement column experiment and reflect the main characteristics of cohesive sediment. The model can be applied to the prediction of cohesive soil settlement in still water environments.展开更多
In order to study deposited sediment settlement and consolidation mechanisms, sediment settlement experiments were conducted using a settlement column. Based on the experimental results, sediment settlement stage defi...In order to study deposited sediment settlement and consolidation mechanisms, sediment settlement experiments were conducted using a settlement column. Based on the experimental results, sediment settlement stage definition, excessive pore pressure （EPP） dissipation, and consolidation constitutive equations are discussed. Three stages, including the free settlement, hindered settlement, and self-weight consolidation settlement stages, are defined. The results of this study show that sediment settlement is mainly affected by the initial sediment concentration and initial settlement height, and the interface settlement rate is linearly attenuated with time on bilogarithmic scales during the hindered settlement and self-weight consolidation settlement stages. Moreover, the deposited sediment layer in the self-weight consolidation settlement stage experiences large strains, and the settlement amount in this stage is about 32% to 59% of the initial height of deposited sediment. EPP is nonlinearly distributed in the settlement direction, and consolidation settlement is faster than EPP dissipation in the self-weight consolidation settlement stage. Consolidation constitutive equations for the hydraulic conductivity and effective stress, applicable to large-strain consolidation calculation, were also determined and fitted in the power function form.展开更多
为了分析隧道浅埋段的地表沉降变形规律,文中以某高速公路隧道为例,对隧道浅埋段的地表纵向及横向沉降量以及沉降量变化速率曲线进行研究。结果表明,随着掌子面距断面距离的增加,A1监测点位置的地表沉降量基本维持在67 mm, A3、A5、A7...为了分析隧道浅埋段的地表沉降变形规律,文中以某高速公路隧道为例,对隧道浅埋段的地表纵向及横向沉降量以及沉降量变化速率曲线进行研究。结果表明,随着掌子面距断面距离的增加,A1监测点位置的地表沉降量基本维持在67 mm, A3、A5、A7监测点位置的地表累计沉降量表现为先快速下降后缓慢下降的变化规律。所有监测断面的地表沉降量分布曲线表现为凸谷的形状,越靠近隧道中心轴线位置,沉降量越大;距离洞口越远,地表沉降量越小。沉降速率值以隧道轴线对称,越靠近隧道轴线的沉降量变化速率越低;随着开挖的推进,且距离洞口越近,沉降量变化速率不断减小。展开更多
基金supported by the Research Funds for the Central Universities (Grant No. 2009B13514)the Doctoral Fund of the Ministry of Education of China (Grant No. 20100094110002)
文摘This paper introduces a slurry suspension settlement prediction model for cohesive sediment in a still water environment. With no sediment input and a still water environment condition, control forces between settling particles are significantly different in the process of sedimentation rate attenuation, and the settlement process includes the free sedimentation stage, the log-linear attenuation stage, and the stable consolidation stage according to sedimentation rate attenuation. Settlement equations for sedimentation height and time were established based on sedimentation rate attenuation properties of different sedimentation stages. Finally, a slurry suspension settlement prediction model based on slurry parameters was set up with a foundation being that the model parameters were determined by the basic parameters of slurry. The results of the settlement prediction model show good agreement with those of the settlement column experiment and reflect the main characteristics of cohesive sediment. The model can be applied to the prediction of cohesive soil settlement in still water environments.
基金supported by the Fundamental Research Funds for the Central Universities(Grant No.2009B13514)the Doctoral Fund of the Ministry of Education of China(Grant No.20100094110002)
文摘In order to study deposited sediment settlement and consolidation mechanisms, sediment settlement experiments were conducted using a settlement column. Based on the experimental results, sediment settlement stage definition, excessive pore pressure （EPP） dissipation, and consolidation constitutive equations are discussed. Three stages, including the free settlement, hindered settlement, and self-weight consolidation settlement stages, are defined. The results of this study show that sediment settlement is mainly affected by the initial sediment concentration and initial settlement height, and the interface settlement rate is linearly attenuated with time on bilogarithmic scales during the hindered settlement and self-weight consolidation settlement stages. Moreover, the deposited sediment layer in the self-weight consolidation settlement stage experiences large strains, and the settlement amount in this stage is about 32% to 59% of the initial height of deposited sediment. EPP is nonlinearly distributed in the settlement direction, and consolidation settlement is faster than EPP dissipation in the self-weight consolidation settlement stage. Consolidation constitutive equations for the hydraulic conductivity and effective stress, applicable to large-strain consolidation calculation, were also determined and fitted in the power function form.
文摘为了分析隧道浅埋段的地表沉降变形规律,文中以某高速公路隧道为例,对隧道浅埋段的地表纵向及横向沉降量以及沉降量变化速率曲线进行研究。结果表明,随着掌子面距断面距离的增加,A1监测点位置的地表沉降量基本维持在67 mm, A3、A5、A7监测点位置的地表累计沉降量表现为先快速下降后缓慢下降的变化规律。所有监测断面的地表沉降量分布曲线表现为凸谷的形状,越靠近隧道中心轴线位置,沉降量越大;距离洞口越远,地表沉降量越小。沉降速率值以隧道轴线对称,越靠近隧道轴线的沉降量变化速率越低;随着开挖的推进,且距离洞口越近,沉降量变化速率不断减小。
