In an effort to investigate and quantify the patterns of local scour,researchers embarked on an in-depth study using a systematic experimental approach.The research focused on the effects of local scour around a set o...In an effort to investigate and quantify the patterns of local scour,researchers embarked on an in-depth study using a systematic experimental approach.The research focused on the effects of local scour around a set of four piles,each subjected to different hydromechanical conditions.In particular,this study aimed to determine how different attack angles—the angles at which the water flow impinges on the piles,and gap ratios—the ratios of the spacing between the piles to their diameters,influence the extent and nature of scour.A comprehensive series of 35 carefully designed experiments were orchestrated,each designed to dissect the nuances in how the gap ratio and attack angle might contribute to changes in the local scour observed at the base of pile groups.During these experimental trials,a wealth of local scour data were collected to support the analysis.These data included precise topographic profiles of the sediment bed around the pile groups,as well as detailed scour time histories showing the evolution of scour at strategic feature points throughout the test procedure.The analysis of the experimental data provided interesting insights.The study revealed that the interplay between the gap ratio and the attack angle had a pronounced influence on the scouring dynamics of the pile groups.One of the key observations was that the initial phases of scour,particularly within the first hour of water flow exposure,were characterized by a sharp increase in the scour depth occurring immediately in front of the piles.After this initial rapid development,the scour depth transitioned to a more gradual change rate.In contrast,the scour topography around the piles continuously evolved.This suggests that sediment displacement and the associated sculpting of the seabed around pile foundations are sustained and progressive processes,altering the underwater landscape over time.The results of this empirical investigation have significant implications for the design and construction of offshore multi-pile foundations,providing a critical reference for engineers and designers to estimate the expected scour depth around such structures,which is an integral part of decisions regarding foundation design,selection of structural materials,and implementation of scour protection measures.展开更多
针对RTK(Real Time Kinematic,简称RTK)和全站仪在变形监测中对高压电塔测量受干扰、不能实时动态监测的问题,根据塔型建筑物对倾斜极为敏感这一特性,运用重力原理,设计了一套自动监测装置,从而实现了高压电塔的实时动态监测。装置主要...针对RTK(Real Time Kinematic,简称RTK)和全站仪在变形监测中对高压电塔测量受干扰、不能实时动态监测的问题,根据塔型建筑物对倾斜极为敏感这一特性,运用重力原理,设计了一套自动监测装置,从而实现了高压电塔的实时动态监测。装置主要包括:自转机构、倾斜测量机构、倾斜报警等。倾斜测量构件采用"精度放大+刻度显示"装置,通过运用齿轮间的传动原理将塔身微倾斜角度放大40倍,提高了测量准确度;同时,通过研制了重力自动旋转装置,实现了自动监测塔身360°方向的倾斜。本设计通过结合机械自动报警与GPS定位技术,实现了高压电塔的安全预警。通过全站仪观测与装置自动监测实验结果对比表明,此装置及自动监测方法可以满足传统变形监测测量的要求。在测量仪器监测高压电塔倾斜受到限制的情况下,采用自动倾斜动态监测装置可以有效地完成电塔的倾斜监测,同时提高了测量效率,为高压电塔的防护监测提供了一条有效途径。展开更多
基金financially supported by the National Natural Science Foundation of China(Grant No.51890913)the Natural Science Foundation of Sichuan Province of China(Grant No.2023YFQ0111)。
文摘In an effort to investigate and quantify the patterns of local scour,researchers embarked on an in-depth study using a systematic experimental approach.The research focused on the effects of local scour around a set of four piles,each subjected to different hydromechanical conditions.In particular,this study aimed to determine how different attack angles—the angles at which the water flow impinges on the piles,and gap ratios—the ratios of the spacing between the piles to their diameters,influence the extent and nature of scour.A comprehensive series of 35 carefully designed experiments were orchestrated,each designed to dissect the nuances in how the gap ratio and attack angle might contribute to changes in the local scour observed at the base of pile groups.During these experimental trials,a wealth of local scour data were collected to support the analysis.These data included precise topographic profiles of the sediment bed around the pile groups,as well as detailed scour time histories showing the evolution of scour at strategic feature points throughout the test procedure.The analysis of the experimental data provided interesting insights.The study revealed that the interplay between the gap ratio and the attack angle had a pronounced influence on the scouring dynamics of the pile groups.One of the key observations was that the initial phases of scour,particularly within the first hour of water flow exposure,were characterized by a sharp increase in the scour depth occurring immediately in front of the piles.After this initial rapid development,the scour depth transitioned to a more gradual change rate.In contrast,the scour topography around the piles continuously evolved.This suggests that sediment displacement and the associated sculpting of the seabed around pile foundations are sustained and progressive processes,altering the underwater landscape over time.The results of this empirical investigation have significant implications for the design and construction of offshore multi-pile foundations,providing a critical reference for engineers and designers to estimate the expected scour depth around such structures,which is an integral part of decisions regarding foundation design,selection of structural materials,and implementation of scour protection measures.
文摘针对RTK(Real Time Kinematic,简称RTK)和全站仪在变形监测中对高压电塔测量受干扰、不能实时动态监测的问题,根据塔型建筑物对倾斜极为敏感这一特性,运用重力原理,设计了一套自动监测装置,从而实现了高压电塔的实时动态监测。装置主要包括:自转机构、倾斜测量机构、倾斜报警等。倾斜测量构件采用"精度放大+刻度显示"装置,通过运用齿轮间的传动原理将塔身微倾斜角度放大40倍,提高了测量准确度;同时,通过研制了重力自动旋转装置,实现了自动监测塔身360°方向的倾斜。本设计通过结合机械自动报警与GPS定位技术,实现了高压电塔的安全预警。通过全站仪观测与装置自动监测实验结果对比表明,此装置及自动监测方法可以满足传统变形监测测量的要求。在测量仪器监测高压电塔倾斜受到限制的情况下,采用自动倾斜动态监测装置可以有效地完成电塔的倾斜监测,同时提高了测量效率,为高压电塔的防护监测提供了一条有效途径。
