This paper put forward the applicable calculation method with the emphasis on theories of the rigid length-short-pile composite foundation strength and settlement.

For multiple?story buildings, when bearing capacit y of ground meets de sign demands, while supporting course is too weak to meet demand of settlement d eformation, if we install rigidity short piles composite ground, combined with t ick course technology, we can not only improve bearing capacity of ground but al so control settlement deformation of buildings.

Engineering characteristics of composite foundation with rigid-flexible and long-short piles;

Analytic method of pile displacement in long-short pile group subjected to vertical loading;

The stresses of long piles,short piles and soil were measured by the tests in situ on the bearing characteristics of cement-soil long-short piles composite foundation in deep soft soils;pile-soil stress ratio of composite foundation with cement-soil long-short piles and its variation rule with the load were studied in deep soils.

The mechanism between load and displacement of long-short pile foundation with end-bearing long-piles can be comprehended profoundly.