The frontal edge of the Makran accretionary wedge is characterized by the development of multiple imbricate thrust faults trending E-W and relatively parallel.However,the mechanisms underlying their formation and the ...The frontal edge of the Makran accretionary wedge is characterized by the development of multiple imbricate thrust faults trending E-W and relatively parallel.However,the mechanisms underlying their formation and the factors controlling their development remain subjects of debate.This paper,based on seismic profile analysis,employs physical simulation experiments to establish a'wedge'type subduction model.The study explores the influence of the initial wedge angle,horizontal sand layer thickness,and the presence or absence of a decollement layer on the structural styles of the thrust wedge.Experimental results indicate that as the initial wedge angle decreases from 11°to 8°,the lateral growth of the thrust wedge increases,whereas vertical growth diminishes.When the horizontal sand layer thickness is reduced from 4.5 cm to 3.0 cm,the spacing between the frontal thrusts decreases and the number of thrust faults increases.Both lateral and vertical growth are relatively reduced,resulting in a smaller thrust wedge.When a decollement layer is present,the structural style exhibits layered deformation.The decollement layer constrains the development of back thrusts and promotes the localized formation of frontal thrusts.In conclusion,the imbricate thrust faults at the frontal edge of the Makran accretionary wedge are primarily controlled by the characteristics of the wedge itself and the presence of the decollement layer.展开更多
We study CO_(2) injection into a saline aquifer intersected by a tectonic fault using a coupled modeling approach to evaluate potential geomechanical risks.The simulation approach integrates the reservoir and mechanic...We study CO_(2) injection into a saline aquifer intersected by a tectonic fault using a coupled modeling approach to evaluate potential geomechanical risks.The simulation approach integrates the reservoir and mechanical simulators through a data transfer algorithm.MUFITS simulates non-isothermal multiphase flow in the reservoir,while FLAC3D calculates its mechanical equilibrium state.We accurately describe the tectonic fault,which consists of damage and core zones,and derive novel analytical closure relations governing the permeability alteration in the fault zone.We estimate the permeability of the activated fracture network in the damage zone and calculate the permeability of the main crack in the fault core,which opens on asperities due to slip.The coupled model is applied to simulate CO_(2) injection into synthetic and realistic reservoirs.In the synthetic reservoir model,we examine the impact of formation depth and initial tectonic stresses on geomechanical risks.Pronounced tectonic stresses lead to inelastic deformations in the fault zone.Regardless of the magnitude of tectonic stress,slip along the fault plane occurs,and the main crack in the fault core opens on asperities,causing CO_(2) leakage out of the storage aquifer.In the realistic reservoir model,we demonstrate that sufficiently high bottomhole pressure induces plastic deformations in the near-wellbore zone,interpreted as rock fracturing,without slippage along the fault plane.We perform a sensitivity analysis of the coupled model,varying the mechanical and flow properties of the storage layers and fault zone to assess fault stability and associated geomechanical risks.展开更多
To study the dynamic response rules of pile foundations of mega-bridges over faults in strong seismic areas,a finite element model of the pile foundation-soil-fault interaction of the Haiwen Bridge is established.The ...To study the dynamic response rules of pile foundations of mega-bridges over faults in strong seismic areas,a finite element model of the pile foundation-soil-fault interaction of the Haiwen Bridge is established.The 0.2-0.6 g peak acceleration of the 5010 seismic waves is input to study the effect of the seismic wave of different intensities and the distance changes between the fault and the pile foundation on the dynamic response of the pile body.The results show that the soil layer covering the bedrock amplifies the peak pile acceleration,and the amplifying effect decreases with increasing seismic wave intensity.However,bedrock has less of an effect on peak acceleration.The relative pile displacement shows the mechanical properties of elastic long piles.The pile foundation generates a large bending moment at the bedrock face and the upper soil layer interface,and a large shear force at the pile top and the soft-hard soil body interface.The relative displacement,bending,and shear bearing characteristics of the pile foundations on the upper and lower plates of the fault are significantly different.The deformation characteristics are affected by faults in a region ten times the pile diameter.Analysis of the dynamic p-y curves shows that the soil resistance on the pile side of the lower plate at the same depth is greater than that of the upper plate.Sensitivity of the dynamic response of pile foundations on either side of the fault to the effects of seismic intensity and distance between the pile foundation and the fault:distance l seismic intensity q.展开更多
在电网调度过程中,存在着高复杂度、快速响应、信号波动等诸多问题。基于专家经验构建的调度模型,已难以满足实时控制的需求。该文针对突发断线故障的电力系统调度场景,提出一种融合模拟运行机制的系统调度策略优化方法。在模仿学习阶段...在电网调度过程中,存在着高复杂度、快速响应、信号波动等诸多问题。基于专家经验构建的调度模型,已难以满足实时控制的需求。该文针对突发断线故障的电力系统调度场景,提出一种融合模拟运行机制的系统调度策略优化方法。在模仿学习阶段,将模拟运行机制与动作空间多级缩减模型相结合,以此压缩动作搜索空间,并利用模拟专家经验数据提升基础调度策略的学习效率;在强化学习阶段,借助模拟运行机制优先选择断线重连动作,从而提升决策准确性;此外,设计差异化奖励函数优化策略引导。断线故障仿真及消融实验表明,该方法相较于双重深度Q网络(double deep Q-network,DDQN)算法模型和模仿学习模型,综合调度成功率分别提高了50%和100%,调度动作成本分别降低了50%和60%,电网稳定运行时间分别是上述两个模型的1.85倍和6.5倍。展开更多
基金the National Natural Science Foundation of China(No.42076069)。
文摘The frontal edge of the Makran accretionary wedge is characterized by the development of multiple imbricate thrust faults trending E-W and relatively parallel.However,the mechanisms underlying their formation and the factors controlling their development remain subjects of debate.This paper,based on seismic profile analysis,employs physical simulation experiments to establish a'wedge'type subduction model.The study explores the influence of the initial wedge angle,horizontal sand layer thickness,and the presence or absence of a decollement layer on the structural styles of the thrust wedge.Experimental results indicate that as the initial wedge angle decreases from 11°to 8°,the lateral growth of the thrust wedge increases,whereas vertical growth diminishes.When the horizontal sand layer thickness is reduced from 4.5 cm to 3.0 cm,the spacing between the frontal thrusts decreases and the number of thrust faults increases.Both lateral and vertical growth are relatively reduced,resulting in a smaller thrust wedge.When a decollement layer is present,the structural style exhibits layered deformation.The decollement layer constrains the development of back thrusts and promotes the localized formation of frontal thrusts.In conclusion,the imbricate thrust faults at the frontal edge of the Makran accretionary wedge are primarily controlled by the characteristics of the wedge itself and the presence of the decollement layer.
文摘We study CO_(2) injection into a saline aquifer intersected by a tectonic fault using a coupled modeling approach to evaluate potential geomechanical risks.The simulation approach integrates the reservoir and mechanical simulators through a data transfer algorithm.MUFITS simulates non-isothermal multiphase flow in the reservoir,while FLAC3D calculates its mechanical equilibrium state.We accurately describe the tectonic fault,which consists of damage and core zones,and derive novel analytical closure relations governing the permeability alteration in the fault zone.We estimate the permeability of the activated fracture network in the damage zone and calculate the permeability of the main crack in the fault core,which opens on asperities due to slip.The coupled model is applied to simulate CO_(2) injection into synthetic and realistic reservoirs.In the synthetic reservoir model,we examine the impact of formation depth and initial tectonic stresses on geomechanical risks.Pronounced tectonic stresses lead to inelastic deformations in the fault zone.Regardless of the magnitude of tectonic stress,slip along the fault plane occurs,and the main crack in the fault core opens on asperities,causing CO_(2) leakage out of the storage aquifer.In the realistic reservoir model,we demonstrate that sufficiently high bottomhole pressure induces plastic deformations in the near-wellbore zone,interpreted as rock fracturing,without slippage along the fault plane.We perform a sensitivity analysis of the coupled model,varying the mechanical and flow properties of the storage layers and fault zone to assess fault stability and associated geomechanical risks.
基金funded by National Natural Science Foundation of China Projects(51708040)Hainan Provincial Transportation Science and Technology Project(HNZXY2015-045R)Changan University Central University Basic Research Business Fund Special Funds(No.300102218115).
文摘To study the dynamic response rules of pile foundations of mega-bridges over faults in strong seismic areas,a finite element model of the pile foundation-soil-fault interaction of the Haiwen Bridge is established.The 0.2-0.6 g peak acceleration of the 5010 seismic waves is input to study the effect of the seismic wave of different intensities and the distance changes between the fault and the pile foundation on the dynamic response of the pile body.The results show that the soil layer covering the bedrock amplifies the peak pile acceleration,and the amplifying effect decreases with increasing seismic wave intensity.However,bedrock has less of an effect on peak acceleration.The relative pile displacement shows the mechanical properties of elastic long piles.The pile foundation generates a large bending moment at the bedrock face and the upper soil layer interface,and a large shear force at the pile top and the soft-hard soil body interface.The relative displacement,bending,and shear bearing characteristics of the pile foundations on the upper and lower plates of the fault are significantly different.The deformation characteristics are affected by faults in a region ten times the pile diameter.Analysis of the dynamic p-y curves shows that the soil resistance on the pile side of the lower plate at the same depth is greater than that of the upper plate.Sensitivity of the dynamic response of pile foundations on either side of the fault to the effects of seismic intensity and distance between the pile foundation and the fault:distance l seismic intensity q.
文摘在电网调度过程中,存在着高复杂度、快速响应、信号波动等诸多问题。基于专家经验构建的调度模型,已难以满足实时控制的需求。该文针对突发断线故障的电力系统调度场景,提出一种融合模拟运行机制的系统调度策略优化方法。在模仿学习阶段,将模拟运行机制与动作空间多级缩减模型相结合,以此压缩动作搜索空间,并利用模拟专家经验数据提升基础调度策略的学习效率;在强化学习阶段,借助模拟运行机制优先选择断线重连动作,从而提升决策准确性;此外,设计差异化奖励函数优化策略引导。断线故障仿真及消融实验表明,该方法相较于双重深度Q网络(double deep Q-network,DDQN)算法模型和模仿学习模型,综合调度成功率分别提高了50%和100%,调度动作成本分别降低了50%和60%,电网稳定运行时间分别是上述两个模型的1.85倍和6.5倍。
