Study On Soil Squeezing Effect Of Wedge Pile

Compared with the traditional prefabricated pipe pile,the wedge-shaped pile has the advantages of giving full play to the side friction resistance,small settlement,les s earthwork required for construction,and high economic benefit.It has been paid m ore and more attention by scholars.However,the research on wedge-shaped piles has focused on the standard value of the vertical ultimate bearing capacity of single piles.There are not many theoretical studies on the squeezing effect of wedge-shaped piles during sinking.Moreover,for open wedge-shaped piles,many scholars ignore the vo lume change of the soil around the pile caused by the soil plug effect.This paper is based on the theory of circular hole expansion in "Elastoplastic Mechanics" and Hai-Sui Yu's "Ground Expansion Theory of Geotechnical Medium",considering the condit ion of soil volume change caused by the soil plug effect,and establishing equal wall thickness unequal wedge Mechanical equilibrium equation of angled wedge-shaped pi les during sinking.Derive the theoretical calculation analytical formula of various data of the soil around the pile during the sinking process of the wedge-shaped pile and establish the theoretical model.A combination of indoor model experiment and discre te element numerical simulation is adopted,compare and analyze the theoretical model curve with the indoor experiment and numerical simulation curve.The main work of this article are:1.The circular hole expansion theory can be used to reasonably predict the end resistance,friction resistance and radial displacement of wedge-shaped piles caused b y squeezing soil during static pressure sinking.However,the theoretical value is slight ly larger than the actual and simulated values.The unloading of the soil around the pile during the driving of the pile body reduces the normal stress of the pile body,a nd the artificially compacted sand is difficult to compact and the compaction effect i s poor,resulting in a gap between the theoretical value and the measured value and the simulated value.2.After considering the volume change of the soil around the pile caused by th e soil plug effect,the yield criterion of some sand bodies adopts the Tresca yield cri terion,then the theoretical derivation can be solved only with the pile and soil engin eering parameters(such as internal and external diameter,pile length,etc.)The e xact solution of the stress and displacement of the soil around the pile.The yield crit erion of some sand bodies adopts Mohr-coulomb yield criterion.The solution of the radial displacement of the soil particles up around the pile contains high-order quantiti es that cannot be solved.the soil pressure on the side of all the wedge-shaped wedge-shaped piles increases continuously before the pile body reaches the measuring point,and remains unchanged or slightly decreases after reaching the measuring point.The porosity of the soil on the side of the pile continues to decrease before the pile bod y reaches the measuring point,and the porosity remains stable or slightly decreases a fter the pile body passes through the measuring point.3.The end resistance and side friction resistance of the wedge-shaped pile conti nue to increase during the sinking of the pile body,and the proportion of the side fr iction resistance in the total sinking resistance continues to increase.After completion of sinking,it exceeds 90%,indicating that the wedge-shaped pile Has the advantage of exerting side friction resistance.4.There is no obvious positive correlation between the size of the wedge angle and the height of the soil plug.The larger the wedge angle,the more soil particles penetrate into the pile,but the height of the soil plug is not necessarily higher.But the increase of the wedge angle will obviously increase the displacement of the parti cles around the pile and the size of the lateral friction resistance.It has basically no effect on the end resistance.But in general,the larger the wedge angle,the greater the proportion of side friction resistance in total friction resistance.