Research On Bearing Capacity At Time Of Jetted Conductor In Deepwater After Installation

At present, the Deepwater jetting drilling technology has been applied more andmore widely, but a unified calculation method has not yet been formed for thecalculation of jetted conductor’s bearing capacity at time, in this paper the finiteelement numerical simulation method is used for the analysis of jetted conductor’sbearing capacity at time, and a calculation method of jetted conductor’s bearingcapacity at time has been suggested. The main research works are as follows:First, Excess pore water pressure has been produced because of the pentrationdisturbance to the surrounding soil by the jetted conductor, so the surrounding soil hasbeen divided into remodeling region and slightly disturbed region. In the remodelingregion, the soil has been disturbed completely in which the excess pore water pressureis equal to the effective overburden pressure. While in the slightly disturbed region,excess pore water pressure has reduced to zero along the diameter direction in6timesof diameter. Further, according to Biot consolidation equation of finite element atinitial excess pore water pressure, through the analysis of excess pore water pressuredissipation in the disturbed soil, the reconsolidation of the disturbed soil around thejetted conductor has been solved. Secondly, in order to establish the relationshipbetween undrained shear strength and different degree of consolidation in the processof disturbed soil’s consolidation, through undrained shear strength recovery test underdifferent confining pressures, the relationship between undrained shear strength anddifferent degree of consolidation in the process of disturbed soil’s consolidation hasbeen solved by the normalized curve of them. Thus the bearing capacity of jettedconductor has been solved through the dissipation of excess pore water pressure.Finally, based on empirical formula, a calculation formula of jetted conductor’sbearing capacity at time has been advised, then the jetted conductor’s bearing capacityat after installing at time on the South China Sea were analysed, and the influence ofremodeling zone of soil on the bearing capacity at time has been discussed.