Based on the results of the field static load test of the screw pile group

some influencing factors of the bearing capacity of screw-pile group is analyzed

and the influences of geometric parameters of pile group on end bearing and friction resistance of pile group under ultimate loading are discussed. From the analysis of testing results

the bearing capacity of screw pile group is obviously influenced by the distance of lamina between screw piles and the length of pile from the first layer of lamina to the base of pile cap. When the ratio of pile spacing of lamina

which is the ratio of the pile spacing to the diameter of lamina

is less than 2

there are not the obvious inflexions and presented the slow change for the load-displacement curve of the static load test of screw-pile group; for these failures of pile group belonged to the general failure. At the same time

the lamina of screw pile is able to promote the reciprocity among pile

soils and pile cap by limiting height of the active zone of deformation of soils under pile cap

and the displacement of pile group is decreased.