A foundation treatment method for piling a foundation structure by penetrating a hardpan layer, i.e., a Deep Slurry Mixing method, comprising following steps: disturbing, by a mechanical device, a location where the foundation structure is to be piled, so that the mechanical device penetrates the hardpan layer of a natural foundation; then injecting clay slurry into the hardpan layer of the natural foundation by a pumping device, an improved foundation is formed after mixing; and piling the foundation structure. The method can change soil property of the original natural foundation, break the hardpan layer, reduce piling resistance of the steel plate cylinder or similar foundation structure, reduce uneven force during the piling process and improve driveability.

A foundation treatment method for piling a foundation structure by penetrating a hardpan layer, i.e., a Deep Slurry Mixing method, comprising following steps: disturbing, by a mechanical device, a location where the foundation structure is to be piled, so that the mechanical device penetrates the hardpan layer of a natural foundation; then injecting clay slurry into the hardpan layer of the natural foundation by a pumping device, an improved foundation is formed after mixing; and piling the foundation structure. The method can change soil property of the original natural foundation, break the hardpan layer, reduce piling resistance of the steel plate cylinder or similar foundation structure, reduce uneven force during the piling process and improve driveability.

A foundation treatment method for piling a foundation structure by penetrating a hardpan layer, i.e., a Deep Slurry Mixing method, comprising following steps: disturbing, by a mechanical device, a location where the foundation structure is to be piled, so that the mechanical device penetrates the hardpan layer of a natural foundation; then injecting clay slurry into the hardpan layer of the natural foundation by a pumping device, an improved foundation is formed after mixing; and piling the foundation structure. The method can change soil property of the original natural foundation, break the hardpan layer, reduce piling resistance of the steel plate cylinder or similar foundation structure, reduce uneven force during the piling process and improve driveability.

A subsea foundation for supporting a pipeline or a pipeline accessory has a mudmat and at least one pile arranged to anchor the mudmat by extending from the mudmat into seabed soil. A coupling that couples the pile to the mudmat has at least one interface member supported for angular displacement relative to the mudmat, such as a pivoting beam or a wedge-shaped adaptor ring, to accommodate the orientation of the mudmat relative to the pile.

A subsea foundation for supporting a pipeline or a pipeline accessory has a mudmat and at least one pile arranged to anchor the mudmat by extending from the mudmat into seabed soil. A coupling that couples the pile to the mudmat has at least one interface member supported for angular displacement relative to the mudmat, such as a pivoting beam or a wedge-shaped adaptor ring, to accommodate the orientation of the mudmat relative to the pile.

A method for preventing sudden subsidence of an open caisson in a soft foundation includes the following steps: a position of the open caisson is determined; grouting is carried out to reinforce a foundation of the open caisson; an open caisson manufacturing site is leveled; sections of the open caisson are manufactured and installed; the step of sections of the open caisson are manufactured and installed is repeated until all the sections are manufactured and the open caisson subsides in place as a whole.

A method for preventing sudden subsidence of an open caisson in a soft foundation includes the following steps: a position of the open caisson is determined; grouting is carried out to reinforce a foundation of the open caisson; an open caisson manufacturing site is leveled; sections of the open caisson are manufactured and installed; the step of sections of the open caisson are manufactured and installed is repeated until all the sections are manufactured and the open caisson subsides in place as a whole.