Based on the characteristics of pile-soil interaction and the Mohr-Coulomb strength theory,a new method of determining the side friction at a pile-soil interaction is proposed.Combined with the actual engineering case...Based on the characteristics of pile-soil interaction and the Mohr-Coulomb strength theory,a new method of determining the side friction at a pile-soil interaction is proposed.Combined with the actual engineering cases,the effectiveness of the analogue test method is verified by comparing it with the traditional anchor pile method and self-balanced method.Taking the self-balanced test of the bridge pile foundation in the Songhua River as an example,the conversion factor of sandy soil and weathered mudstone are confirmed by the analogue test method.The results show that the conversion factor of sandy soil and weathered mudstone in the Songhua River area should consider the geological conditions and the construction technology,etc.The standard values are relatively conservative.It is suggested that the engineering application should be properly revised.The recommended range of the conversion factor of sandy soil in this area is 0.65 to 0.85,and that of weathered mudstone is 1.0.展开更多
The measurement of pile axial load is of great significance to determining pile foundation design parameters such as skin friction and end bearing capacity and analyzing load transfer mechanisms.Affected by the temper...The measurement of pile axial load is of great significance to determining pile foundation design parameters such as skin friction and end bearing capacity and analyzing load transfer mechanisms.Affected by the temperature and ice content of frozen ground,the interface contact relationship between pile foundation and frozen soil is complicated,making pile axial load measurements more uncertain than that in non-frozen ground.Therefore,it is necessary to gain an in-depth understanding of the current pile axial load test methods.Four methods are systematically reviewed:vibrating wire sensors,strain gauges,sliding micrometers,and optical fiber strain sensors.At the same time,the applicability of the four test methods in frozen soil regions is discussed in detail.The first two methods are mature and commonly used.The sliding micrometer is only suitable for short-term measurement.While the Fiber Bragg grating(FBG)strain gauge meets the monitoring requirements,the Brillouin optical time-domain reflectometer(BOTDR)needs further verification.This paper aims to provide a technical reference for selecting and applying different methods in the pile axial load test for the stability study and bearing capacity assessment of pile foundations in cold regions.展开更多
为深入研究螺纹钻压灌桩的抗拔承载特性,开展了3组现场竖向抗拔静载试验,建立了三维有限元模型,分析了抗拔承载力的影响因素,并建立基于灰狼优化(grey wolf optimizer,GWO)算法的数据分组处理方法(group method of data handling,GMDH)...为深入研究螺纹钻压灌桩的抗拔承载特性,开展了3组现场竖向抗拔静载试验,建立了三维有限元模型,分析了抗拔承载力的影响因素,并建立基于灰狼优化(grey wolf optimizer,GWO)算法的数据分组处理方法(group method of data handling,GMDH)模型,对螺纹钻压灌桩抗拔承载力进行预测。结果表明:桩周岩土体物理力学性质越好,螺纹钻压灌桩的抗拔力越强;桩土界面参数对螺纹钻压灌桩抗拔力的影响较小;随着螺纹间距与螺牙宽度的不断增大,螺纹钻压灌桩抗拔承载力呈现先增大后减小的趋势;所建立的GWO-GMDH模型可用于螺纹钻压灌桩抗拔承载力预测。展开更多
基金The National Key Research and Development Program(No.2017YFC0703408)the National Natural Science Foundation of China(No.51478109,51678145,51878160)
文摘Based on the characteristics of pile-soil interaction and the Mohr-Coulomb strength theory,a new method of determining the side friction at a pile-soil interaction is proposed.Combined with the actual engineering cases,the effectiveness of the analogue test method is verified by comparing it with the traditional anchor pile method and self-balanced method.Taking the self-balanced test of the bridge pile foundation in the Songhua River as an example,the conversion factor of sandy soil and weathered mudstone are confirmed by the analogue test method.The results show that the conversion factor of sandy soil and weathered mudstone in the Songhua River area should consider the geological conditions and the construction technology,etc.The standard values are relatively conservative.It is suggested that the engineering application should be properly revised.The recommended range of the conversion factor of sandy soil in this area is 0.65 to 0.85,and that of weathered mudstone is 1.0.
基金This study was supported by the Strategic Priority Research Program of the Chinese Academy of Science(Grant No.XDA20020102)Science and Technology Project of State Grid Corporation of China(Contract No.SGQHDKYOSBJS201600077)+1 种基金National Natural Science Foundation of China(Grant No.41101065)the State Key Laboratory of Frozen Soil Engineering Foundation(Grant No.SKLFSE-ZT-34)。
文摘The measurement of pile axial load is of great significance to determining pile foundation design parameters such as skin friction and end bearing capacity and analyzing load transfer mechanisms.Affected by the temperature and ice content of frozen ground,the interface contact relationship between pile foundation and frozen soil is complicated,making pile axial load measurements more uncertain than that in non-frozen ground.Therefore,it is necessary to gain an in-depth understanding of the current pile axial load test methods.Four methods are systematically reviewed:vibrating wire sensors,strain gauges,sliding micrometers,and optical fiber strain sensors.At the same time,the applicability of the four test methods in frozen soil regions is discussed in detail.The first two methods are mature and commonly used.The sliding micrometer is only suitable for short-term measurement.While the Fiber Bragg grating(FBG)strain gauge meets the monitoring requirements,the Brillouin optical time-domain reflectometer(BOTDR)needs further verification.This paper aims to provide a technical reference for selecting and applying different methods in the pile axial load test for the stability study and bearing capacity assessment of pile foundations in cold regions.
文摘为深入研究螺纹钻压灌桩的抗拔承载特性,开展了3组现场竖向抗拔静载试验,建立了三维有限元模型,分析了抗拔承载力的影响因素,并建立基于灰狼优化(grey wolf optimizer,GWO)算法的数据分组处理方法(group method of data handling,GMDH)模型,对螺纹钻压灌桩抗拔承载力进行预测。结果表明:桩周岩土体物理力学性质越好,螺纹钻压灌桩的抗拔力越强;桩土界面参数对螺纹钻压灌桩抗拔力的影响较小;随着螺纹间距与螺牙宽度的不断增大,螺纹钻压灌桩抗拔承载力呈现先增大后减小的趋势;所建立的GWO-GMDH模型可用于螺纹钻压灌桩抗拔承载力预测。
