This thesis introduces one method for foundation strengthen-jet grouting technology for double pipes and double mixing liquid in designing and construction.

Aim at current disadvantage of bare tugging in dual tubing well,a new seal for bare tubing is developed.

With the processing of evaporation and the increase of the liquid concentration,the periphery of film dropping tube cannot wetted sufficiently,thus,the use of double tube sides is necessary.

An integral core rod, a round-hole diffluent bracket and an extrusion head with double tubes to the extrusion head were applied in extrusion head designing,and the designing process of the ex-trusion head was introduced in detail.

In this paper,the centering technological fundamental principle of synchronization and automation, the construction, the characteristics and its application contrast for dual pipe twist of WLZ Ⅱtype centrifugal casting machine were introduced.