Pyramidal Piles Research Articles

Experimental investigations of piles cast in a punched recess under a vertical load

1. The embedment resistance of a pyramidal pile cast in a punched recess and a driven pile can be considered identical in clay soils of highly plastic and semihard consistencies, while that of the cast pile is smaller in clay soils of fluid and fluid-plastic consistencies. 2. The bearing capacity of a pile cast in a punched recess using the same plate during embedment in the upper portion of slightly compressible soils can be increased by installing a cap with a section larger than that of the pile. 3. The frictional resistance of a cohesive soil along the lateral surface of piles in a punched recess is lower than that along the lateral surface of a probe with a friction coupling, i.e., using an S-832-type probe apparatus; in determining the bearing capacity of these piles using probe data, appropriate reduction factors should therefore be introduced.

Investigation of the bearing capacity of pyramidal piles : Bakholdin, B V; Igonkin, L T Soil Mech Found Engng, V15, N3, May–June 1978, P165–170

Investigation of the bearing capacity of pyramidal piles : Bakholdin, B V; Igonkin, L T Soil Mech Found Engng, V15, N3, May–June 1978, P165–170

Introduction of rectangular pyramidal piles in Belorussia

1. The investigations corroborate the results of well-known theoretical and practical studies on the effect of the geometric shape of piles on their bearing capacity. A computational analysis and model and full-scale pile tests established some quantitative relationships between the bearing capacity and shape of driven piles currently being used in construction. 2. Investigations and construction experience indicate that there is no "universal" pile which is optimal for all structures and all types of soil conditions. According to the results of investigations of short driven piles, and from design and construction experience, it can be concluded that for loose and medium-density, homogeneous sands and clay soils having a consistency ranging from semistiff to soft/plastic, it is expedient to adopt rectangular pyramidal piles for large-scale construction in the conditions in Belorussia, instead of the prismatic type, as they have shown that, under the above conditions, the volume of pile work is reduced 1.6 times, and labor consumption and costs are reduced commensurately.

Use of pyramidal piles for greenhouse foundations : Lazarov, G B Soil Mech Found Engng, V14, N1, Jan–Feb 1977, P20–22

Use of pyramidal piles for greenhouse foundations : Lazarov, G B Soil Mech Found Engng, V14, N1, Jan–Feb 1977, P20–22

Investigation of the bearing capacity of pyramidal piles

1. Pyramidal piles work most effectively not in the zone of their maximum cross section but beginning with a depth of 0.5–1 m from the ground surface, and therefore it is economically advisable to provide for a prismatic part in the upper end of the pyramidal pile. 2. An increase of bearing capacity of the pyramidal pile in comparison with prismatic is achieved as a consequence of the occurrence in the soil during their penetration of a passive earth pressure\(\sigma _{pa_2 } \) which provides additional skin friction. 3. The passive earth pressure and consequently the additional resistance of the pyramidal pile due to the arising thrust do not depend on depth, and within the length of the pile they vary inversely proportional to the size of the side of the pile cross section. 4. The additional skin friction of the pyramidal pile is greater, the greater the modulus of deformation of the soil and its angle of internal friction. 5. It is most advisable to use pyramidal piles at sites composed of soils homogeneous depthwise or in the case of a decrease of deformation and strength characteristics with depth. The maximum effect from the use of pyramidal piles can be obtained only in soils having relatively high moduli of deformation and angles of internal frictions, i.e., in sands, loamy sands, loams with a small plasticity index, loesslike loams, and loess. Pyramidal piles are not effective in clays having a high plasticity, whose strength properties depend mainly on cohesion.

Field studies of bearing ground deformation beneath single pyramidal piles and beneath pile foundations.- In Russian : Osnovaniia I Fundamenty,V6,1973,P84–88

Field studies of bearing ground deformation beneath single pyramidal piles and beneath pile foundations.- In Russian : Osnovaniia I Fundamenty,V6,1973,P84–88