APPLICATION OF UNDERPINNING BY MANUAL PIPE-JACKING IN THE CONSERVATION OF HISTORICAL MASONRY CONSTRUCTIONS

The structural damages,which result from the inadequate bearing capacity or the asymmetric support of foundation,are one of the crucial works in the conservation of historical masonry constructions.Firstly,the box girders are slowly and evenly jacked by the manual pipe jacking technique,and then casting the core beam to form a whole,so the construction is gradually situated on a traywith sufficient rigidity.Consequently,the structural damages caused by the inadequate bearing capacity or the asymmetric support of foundation are thoroughly treated.According to a practical engineering,the principle of the underpinning by manual pipe-jacking,the design of the box-section beam,the techniques of jacking are investigated in detail,and some suggestions and specific implementation measures are presented.