Determining earth pressure on jacked pipes is essential for ensuring lining safety and calculating jacking force,especially for deep-buried pipes.To better reflect the soil arching effect resulting from the excavation...Determining earth pressure on jacked pipes is essential for ensuring lining safety and calculating jacking force,especially for deep-buried pipes.To better reflect the soil arching effect resulting from the excavation of rectangular jacked pipes and the distribution of the earth pressure on jacked pipes,we present an analytical solution for predicting the vertical earth pressure on deep-buried rectangular pipe jacking tunnels,incorporating the tunnelling-induced ground loss distribution.Our proposed analytical model consists of the upper multi-layer parabolic soil arch and the lower friction arch.The key parameters(i.e.,width and height of friction arch B and height of parabolic soil arch H 1)are determined according to the existing research,and an analytical solution for K l is derived based on the distribution characteristics of the principal stress rotation angle.With consideration for the transition effect of the mechanical characteristics of the parabolic arch zone,an analytical solution for soil load transfer is derived.The prediction results of our analytical solution are compared with tests and simulation results to validate the effectiveness of the proposed analytical solution.Finally,the effects of different parameters on the soil pressure are discussed.展开更多
The elastic differential equations of load-transfer of single pile either with applied loads on pile-top or only under the soil swelling were established,respectively,based on the theory of pile-soil interaction and t...The elastic differential equations of load-transfer of single pile either with applied loads on pile-top or only under the soil swelling were established,respectively,based on the theory of pile-soil interaction and the shear-deformation method.The derivation of analytic solution to load-transfer for single pile in expansive soil could hereby be obtained by means of superposition principle under expansive soils swelling.The comparison of two engineering examples was made to prove the credibility of the suggested method.The analyzed results show that this analytic solution can achieve high precision with few parameters required,indicating its' simplicity and practicability in engineering application.The employed method can contribute to determining the greatest tension along pile shaft resulting from expansive soils swelling and provide reliable bases for engineering design.The method can be employed to obtain various distributive curves of axial force,settlements and skin friction along the pile shaft with the changes of active depth,vertical movements of the surface and loads of pile-top.展开更多
The load transfer analytical method is applied to study the bearing mechanism of piles with vertical load in this paper. According to the different hardening rules of soil or rock around the pile shaft, such as work-s...The load transfer analytical method is applied to study the bearing mechanism of piles with vertical load in this paper. According to the different hardening rules of soil or rock around the pile shaft, such as work-softening, ideal elasto-plastic and work-hardening, a universal tri-linear load transfer model is suggested for the development of side and tip resistance by various types of soil (rock) with the consideration of sediment at the bottom of the pile. Based on the model, a formula is derived for the relationship between the settlement and load on the pile top to determine the vertical bearing capacity, taking into account such factors as the characteristics of the stratum, the side resistance along the shaft, and tip resistance under the pile tip. A close agreement of the calculated results with the measured data from a field test pile lends confidence to the future application of the present approach in engineering practice.展开更多
Prestressed high-strength-concrete (PHC) tube-shaped pile is one of the recently used foundations for soft soil. The research on uplift resistance of PHC pile is helpful to the design of pile foundations. A field-scal...Prestressed high-strength-concrete (PHC) tube-shaped pile is one of the recently used foundations for soft soil. The research on uplift resistance of PHC pile is helpful to the design of pile foundations. A field-scale test program was conducted to study the uplift behavior and load transfer mechanism of PHC piles in soft soil. The pullout load tests were divided into two groups with different diameters, and there were three piles in each group. A detailed discussion of the axial load transfer and pile skin resistance distribution was also included. It is found from the tests that the uplift capacity increases with increasing the diameter of pile. When the diameter of piles increases from 500 to 600 mm, the uplift load is increased by 51.2%. According to the load-displacement (Q-S) curves, all the piles do not reach the ultimate state at the maximum load. The experimental results show that the piles still have uplift bearing capacity.展开更多
城市电网在发生N-1故障后,极可能新增运行风险,导致N-1-1时出现大面积停电事故。为管控城市电网N-1后运行风险,该文提出一种改进双智能体竞争双深度Q网络(dueling double deep Q network,D3QN)的城市电网N-1风险管控转供策略。根据风险...城市电网在发生N-1故障后,极可能新增运行风险,导致N-1-1时出现大面积停电事故。为管控城市电网N-1后运行风险,该文提出一种改进双智能体竞争双深度Q网络(dueling double deep Q network,D3QN)的城市电网N-1风险管控转供策略。根据风险管控原则,提出一种无需额外历史数据、考虑备自投装置、单供变电站风险和单供负荷母线风险的N-1场景指标;建立计及动作次序、指标间关系的负荷转供三阶段求解模型。以含预动作-变化探索值选择策略的改进双智能体D3QN方法,将负荷转供分为多个子转供环节学习,使转供思路清晰化,对动作空间进行降维,提高训练寻优效果,得到管控N-1风险的负荷转供策略。通过城市电网多场景算例分析,验证该文模型和方法的有效性。展开更多
基于数据驱动的方法已广泛应用于电力负荷预测领域,以提升预测精度。然而,当售电公司接入新用户时,由于缺乏用户历史用电数据,常规数据驱动方法的适用性会受到一定限制。为解决这一问题,文章提出了一种基于域对抗迁移网络(domain advers...基于数据驱动的方法已广泛应用于电力负荷预测领域,以提升预测精度。然而,当售电公司接入新用户时,由于缺乏用户历史用电数据,常规数据驱动方法的适用性会受到一定限制。为解决这一问题,文章提出了一种基于域对抗迁移网络(domain adversarial transfer network,DATN)的短期电力负荷预测方法。该模型利用Transformer模型作为特征提取器,以捕捉负荷数据中的动态特征和时间依赖性。随后,负荷预测器基于这些特征精准预测未来的负荷情况。通过域判别器与特征提取器的对抗学习,确保模型能够学习到深层域不变特征,同时结合多核最大均值差异(multi-kernel maximum mean discrepancy,MK-MMD)和相关性对齐(correlation alignment,CORAL)进一步减小源域与目标域数据的分布差异。所提模型在南方某省工业用户的用电数据上进行了验证,实验结果表明,在小样本场景下,该方法具备较好的预测精度和场景适应性。展开更多
为解决深度学习预测模型在数据不足时准确性受限的问题,提出一种结合Transformer的交叉注意力(cross-attention in Transformer,CATrans)机制和域分离网络(domain separation networks,DSN)的深度迁移学习方法——CATrans-DSN,用于短期...为解决深度学习预测模型在数据不足时准确性受限的问题,提出一种结合Transformer的交叉注意力(cross-attention in Transformer,CATrans)机制和域分离网络(domain separation networks,DSN)的深度迁移学习方法——CATrans-DSN,用于短期跨建筑负荷预测。CATrans特征提取器利用注意力机制来学习源域和目标域负荷数据的域共有和私有时间特征,并利用共有特征进行知识迁移;特征重构器作为辅助模块,对源域和目标域数据进行数据重构;由回归预测器将学习到的特征转化为预测值。最后,利用在源域和目标域上训练得到的建筑负荷预测模型,直接用于目标建筑的负荷预测。实验结果表明,所提出的方法有效地提高了数据稀缺情况下的预测准确性和模型泛化能力。展开更多
基金Project(2022YJS073)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(2024YFE0198500)supported by the National Key Research and Development Program of China:Intergovernmental International Science and Technology Innovation CooperationProject(U2469207)supported by the National Natural Science Foundation Railway Innovation and Development Joint Fund Project,China。
文摘Determining earth pressure on jacked pipes is essential for ensuring lining safety and calculating jacking force,especially for deep-buried pipes.To better reflect the soil arching effect resulting from the excavation of rectangular jacked pipes and the distribution of the earth pressure on jacked pipes,we present an analytical solution for predicting the vertical earth pressure on deep-buried rectangular pipe jacking tunnels,incorporating the tunnelling-induced ground loss distribution.Our proposed analytical model consists of the upper multi-layer parabolic soil arch and the lower friction arch.The key parameters(i.e.,width and height of friction arch B and height of parabolic soil arch H 1)are determined according to the existing research,and an analytical solution for K l is derived based on the distribution characteristics of the principal stress rotation angle.With consideration for the transition effect of the mechanical characteristics of the parabolic arch zone,an analytical solution for soil load transfer is derived.The prediction results of our analytical solution are compared with tests and simulation results to validate the effectiveness of the proposed analytical solution.Finally,the effects of different parameters on the soil pressure are discussed.
基金Projects(50378097, 50678177) supported by the National Natural Science Foundation of China
文摘The elastic differential equations of load-transfer of single pile either with applied loads on pile-top or only under the soil swelling were established,respectively,based on the theory of pile-soil interaction and the shear-deformation method.The derivation of analytic solution to load-transfer for single pile in expansive soil could hereby be obtained by means of superposition principle under expansive soils swelling.The comparison of two engineering examples was made to prove the credibility of the suggested method.The analyzed results show that this analytic solution can achieve high precision with few parameters required,indicating its' simplicity and practicability in engineering application.The employed method can contribute to determining the greatest tension along pile shaft resulting from expansive soils swelling and provide reliable bases for engineering design.The method can be employed to obtain various distributive curves of axial force,settlements and skin friction along the pile shaft with the changes of active depth,vertical movements of the surface and loads of pile-top.
文摘The load transfer analytical method is applied to study the bearing mechanism of piles with vertical load in this paper. According to the different hardening rules of soil or rock around the pile shaft, such as work-softening, ideal elasto-plastic and work-hardening, a universal tri-linear load transfer model is suggested for the development of side and tip resistance by various types of soil (rock) with the consideration of sediment at the bottom of the pile. Based on the model, a formula is derived for the relationship between the settlement and load on the pile top to determine the vertical bearing capacity, taking into account such factors as the characteristics of the stratum, the side resistance along the shaft, and tip resistance under the pile tip. A close agreement of the calculated results with the measured data from a field test pile lends confidence to the future application of the present approach in engineering practice.
基金Project(50621062) supported by the National Natural Science Foundation of China
文摘Prestressed high-strength-concrete (PHC) tube-shaped pile is one of the recently used foundations for soft soil. The research on uplift resistance of PHC pile is helpful to the design of pile foundations. A field-scale test program was conducted to study the uplift behavior and load transfer mechanism of PHC piles in soft soil. The pullout load tests were divided into two groups with different diameters, and there were three piles in each group. A detailed discussion of the axial load transfer and pile skin resistance distribution was also included. It is found from the tests that the uplift capacity increases with increasing the diameter of pile. When the diameter of piles increases from 500 to 600 mm, the uplift load is increased by 51.2%. According to the load-displacement (Q-S) curves, all the piles do not reach the ultimate state at the maximum load. The experimental results show that the piles still have uplift bearing capacity.
文摘城市电网在发生N-1故障后,极可能新增运行风险,导致N-1-1时出现大面积停电事故。为管控城市电网N-1后运行风险,该文提出一种改进双智能体竞争双深度Q网络(dueling double deep Q network,D3QN)的城市电网N-1风险管控转供策略。根据风险管控原则,提出一种无需额外历史数据、考虑备自投装置、单供变电站风险和单供负荷母线风险的N-1场景指标;建立计及动作次序、指标间关系的负荷转供三阶段求解模型。以含预动作-变化探索值选择策略的改进双智能体D3QN方法,将负荷转供分为多个子转供环节学习,使转供思路清晰化,对动作空间进行降维,提高训练寻优效果,得到管控N-1风险的负荷转供策略。通过城市电网多场景算例分析,验证该文模型和方法的有效性。
文摘基于数据驱动的方法已广泛应用于电力负荷预测领域,以提升预测精度。然而,当售电公司接入新用户时,由于缺乏用户历史用电数据,常规数据驱动方法的适用性会受到一定限制。为解决这一问题,文章提出了一种基于域对抗迁移网络(domain adversarial transfer network,DATN)的短期电力负荷预测方法。该模型利用Transformer模型作为特征提取器,以捕捉负荷数据中的动态特征和时间依赖性。随后,负荷预测器基于这些特征精准预测未来的负荷情况。通过域判别器与特征提取器的对抗学习,确保模型能够学习到深层域不变特征,同时结合多核最大均值差异(multi-kernel maximum mean discrepancy,MK-MMD)和相关性对齐(correlation alignment,CORAL)进一步减小源域与目标域数据的分布差异。所提模型在南方某省工业用户的用电数据上进行了验证,实验结果表明,在小样本场景下,该方法具备较好的预测精度和场景适应性。
文摘为解决深度学习预测模型在数据不足时准确性受限的问题,提出一种结合Transformer的交叉注意力(cross-attention in Transformer,CATrans)机制和域分离网络(domain separation networks,DSN)的深度迁移学习方法——CATrans-DSN,用于短期跨建筑负荷预测。CATrans特征提取器利用注意力机制来学习源域和目标域负荷数据的域共有和私有时间特征,并利用共有特征进行知识迁移;特征重构器作为辅助模块,对源域和目标域数据进行数据重构;由回归预测器将学习到的特征转化为预测值。最后,利用在源域和目标域上训练得到的建筑负荷预测模型,直接用于目标建筑的负荷预测。实验结果表明,所提出的方法有效地提高了数据稀缺情况下的预测准确性和模型泛化能力。
