为了研究桩撑支护的深基坑在开挖过程中混凝土支撑的轴力特性,本文以珠海地区深基坑为典型案例,分析了基坑开挖过程中支撑轴力监测值的时序特征,研究了计算值与监测值之间的关系。针对轴力现场监测值超过警戒值、基坑未开挖时轴力持续...为了研究桩撑支护的深基坑在开挖过程中混凝土支撑的轴力特性,本文以珠海地区深基坑为典型案例,分析了基坑开挖过程中支撑轴力监测值的时序特征,研究了计算值与监测值之间的关系。针对轴力现场监测值超过警戒值、基坑未开挖时轴力持续增加等情况,从荷载、温度、徐变和收缩4个方面进行了分析,揭示了基坑在开挖过程中支撑轴力的演化机制。研究表明:(1)随着基坑开挖深度的增加,支撑轴力均表现出增大的趋势;基坑开挖到底后,第1、2层支撑轴力现场监测值是理论计算值的1.67~3.52倍。(2)温度对轴力有明显的影响,达68 k N/℃;收缩及徐变的影响更大,约为轴力现场监测值的1/3。(3)根据拆撑前后的实测数据,切断支撑消除外荷载后,应力计仍能测到轴力,约为未切断前轴力的60%。本文研究结果可为深基坑支撑设计、施工和监测提供参考。展开更多
It is desirable to get a uniform load distribution for the pressure rollers of the mangle.In thispaper,the load uniforming principle of the axially-staggered pressure rollers and the rules for theroller design have be...It is desirable to get a uniform load distribution for the pressure rollers of the mangle.In thispaper,the load uniforming principle of the axially-staggered pressure rollers and the rules for theroller design have been analysed by the theory of bending of beams.The ratio of maximum tominimum value of the distributed load in the nip being taken as a useful index to describe the uni-formity of the load distribution,the performance of the so-called load-uniforming pressure rollerswith rubber covering,under various operation conditions,has been evaluated.As a result,it isproved that the load-uniforming pressure rollers with axially-staggered contact is a pratically use-ful means of uniformizing the load distribution,which ensures that the mangle will squeeze the ma-terial to be processed uniformly over its whole width under any technological load,and needs onlysome simple regulations.The conclusions obtained in this paper can easily be extended to the pressure rollers with anysupport conditions.展开更多
文摘为了研究桩撑支护的深基坑在开挖过程中混凝土支撑的轴力特性,本文以珠海地区深基坑为典型案例,分析了基坑开挖过程中支撑轴力监测值的时序特征,研究了计算值与监测值之间的关系。针对轴力现场监测值超过警戒值、基坑未开挖时轴力持续增加等情况,从荷载、温度、徐变和收缩4个方面进行了分析,揭示了基坑在开挖过程中支撑轴力的演化机制。研究表明:(1)随着基坑开挖深度的增加,支撑轴力均表现出增大的趋势;基坑开挖到底后,第1、2层支撑轴力现场监测值是理论计算值的1.67~3.52倍。(2)温度对轴力有明显的影响,达68 k N/℃;收缩及徐变的影响更大,约为轴力现场监测值的1/3。(3)根据拆撑前后的实测数据,切断支撑消除外荷载后,应力计仍能测到轴力,约为未切断前轴力的60%。本文研究结果可为深基坑支撑设计、施工和监测提供参考。
文摘It is desirable to get a uniform load distribution for the pressure rollers of the mangle.In thispaper,the load uniforming principle of the axially-staggered pressure rollers and the rules for theroller design have been analysed by the theory of bending of beams.The ratio of maximum tominimum value of the distributed load in the nip being taken as a useful index to describe the uni-formity of the load distribution,the performance of the so-called load-uniforming pressure rollerswith rubber covering,under various operation conditions,has been evaluated.As a result,it isproved that the load-uniforming pressure rollers with axially-staggered contact is a pratically use-ful means of uniformizing the load distribution,which ensures that the mangle will squeeze the ma-terial to be processed uniformly over its whole width under any technological load,and needs onlysome simple regulations.The conclusions obtained in this paper can easily be extended to the pressure rollers with anysupport conditions.
