随着城市化进程中地下空间开发及抗浮问题的凸显,抗拔桩在东南沿海等高水位黏性土地区的应用日益广泛,然而常规钻孔施工工艺面临诸多挑战,如泥皮效应导致桩侧阻力难以达标、扩底成孔困难等。为此,提出考虑扰动效应的束浆挤扩桩抗拔承载...随着城市化进程中地下空间开发及抗浮问题的凸显,抗拔桩在东南沿海等高水位黏性土地区的应用日益广泛,然而常规钻孔施工工艺面临诸多挑战,如泥皮效应导致桩侧阻力难以达标、扩底成孔困难等。为此,提出考虑扰动效应的束浆挤扩桩抗拔承载力计算方法。以上海第(5)1层灰色黏土为对象,建立黏土和砂的弹塑性扰动状态(clay and sand elastic-plastic-disturbed state concept,简称CASM-DSC)模型,精确模拟桩周地基土力学特性。通过用户自定义材料本构(user-defined material mechanical behavior,简称UMAT)子程序,开展数值模拟,分析桩周地基土及挤扩尺寸的扰动效应。修正前期研究的束浆挤扩钢管桩抗拔简化计算方法。结果表明,钻孔开挖显著削弱黏性土的侧阻力,影响桩-土界面的力学性能,扰动系数和范围对地基土应力状态呈二次曲线和线性折减关系。在不同的挤扩长度下,模型桩的极限抗拔承载力随长度增加呈“V”字型特点,且挤扩工艺可改变桩侧受力面积与轴力分布。通过上海徐汇滨江地块的现场试验,验证了简化计算方法的有效性与适用性,其计算误差控制在15%以内,为桩基础工程设计提供了可靠的理论支持与实用计算方法。展开更多
For the carbon-neutral,a multi-carrier renewable energy system(MRES),driven by the wind,solar and geothermal,was considered as an effective solution to mitigate CO2emissions and reduce energy usage in the building sec...For the carbon-neutral,a multi-carrier renewable energy system(MRES),driven by the wind,solar and geothermal,was considered as an effective solution to mitigate CO2emissions and reduce energy usage in the building sector.A proper sizing method was essential for achieving the desired 100%renewable energy system of resources.This paper presented a bi-objective optimization formulation for sizing the MRES using a constrained genetic algorithm(GA)coupled with the loss of power supply probability(LPSP)method to achieve the minimal cost of the system and the reliability of the system to the load real time requirement.An optimization App has been developed in MATLAB environment to offer a user-friendly interface and output the optimized design parameters when given the load demand.A case study of a swimming pool building was used to demonstrate the process of the proposed design method.Compared to the conventional distributed energy system,the MRES is feasible with a lower annual total cost(ATC).Additionally,the ATC decreases as the power supply reliability of the renewable system decreases.There is a decrease of 24%of the annual total cost when the power supply probability is equal to 8%compared to the baseline case with 0%power supply probability.展开更多
文摘随着城市化进程中地下空间开发及抗浮问题的凸显,抗拔桩在东南沿海等高水位黏性土地区的应用日益广泛,然而常规钻孔施工工艺面临诸多挑战,如泥皮效应导致桩侧阻力难以达标、扩底成孔困难等。为此,提出考虑扰动效应的束浆挤扩桩抗拔承载力计算方法。以上海第(5)1层灰色黏土为对象,建立黏土和砂的弹塑性扰动状态(clay and sand elastic-plastic-disturbed state concept,简称CASM-DSC)模型,精确模拟桩周地基土力学特性。通过用户自定义材料本构(user-defined material mechanical behavior,简称UMAT)子程序,开展数值模拟,分析桩周地基土及挤扩尺寸的扰动效应。修正前期研究的束浆挤扩钢管桩抗拔简化计算方法。结果表明,钻孔开挖显著削弱黏性土的侧阻力,影响桩-土界面的力学性能,扰动系数和范围对地基土应力状态呈二次曲线和线性折减关系。在不同的挤扩长度下,模型桩的极限抗拔承载力随长度增加呈“V”字型特点,且挤扩工艺可改变桩侧受力面积与轴力分布。通过上海徐汇滨江地块的现场试验,验证了简化计算方法的有效性与适用性,其计算误差控制在15%以内,为桩基础工程设计提供了可靠的理论支持与实用计算方法。
基金Project(52108101)supported by the National Natural Science Foundation of ChinaProjects(2020GK4057,2021JJ40759)supported by the Hunan Provincial Science and Technology Department,China。
文摘For the carbon-neutral,a multi-carrier renewable energy system(MRES),driven by the wind,solar and geothermal,was considered as an effective solution to mitigate CO2emissions and reduce energy usage in the building sector.A proper sizing method was essential for achieving the desired 100%renewable energy system of resources.This paper presented a bi-objective optimization formulation for sizing the MRES using a constrained genetic algorithm(GA)coupled with the loss of power supply probability(LPSP)method to achieve the minimal cost of the system and the reliability of the system to the load real time requirement.An optimization App has been developed in MATLAB environment to offer a user-friendly interface and output the optimized design parameters when given the load demand.A case study of a swimming pool building was used to demonstrate the process of the proposed design method.Compared to the conventional distributed energy system,the MRES is feasible with a lower annual total cost(ATC).Additionally,the ATC decreases as the power supply reliability of the renewable system decreases.There is a decrease of 24%of the annual total cost when the power supply probability is equal to 8%compared to the baseline case with 0%power supply probability.
