Experimental and Numerical Analysis of Pile–Rock Interaction Characteristics of Steel Pipe Piles Penetrating into Coral Reef Limestone

Abstract

In order to study the characteristics of pile–rock action of steel pipe driven pile in coral reef limestone stratum, coral reef limestone at the China–Maldives Friendship Bridge site was selected to carry out indoor physical and model tests with red sandstone as the control group. The test outcomes indicate the following: (1) when substantial deformation is permitted, the coral reef limestone has a considerable strength dispersion, a low post-peak stress decrease rate, and a high residual strength, roughly 30% of the peak strength; (2) when the steel pipe pile penetrates the coral reef limestone, the pile top load shows an obvious sawtooth shape, and with the increase in penetration depth, the pile end load of the high-porosity rock sample gradually decreases, and the pile end load of the low-porosity rock sample gradually increases; (3) when the steel pipe pile is penetrated, the strain value of the red sandstone is about twice that of the coral reef limestone at the same position from the steel pipe pile. These findings indicate that the high porosity and heterogeneity cementation characteristics of the coral reef limestone make the extrusion effect during piling significantly less than that of the red sandstone. In addition, the steel pipe pile penetration process is numerically simulated using a four-dimensional discrete spring model method based on the multi-body damage criterion. The numerical simulation results further demonstrate that the pile-side rock fragmentation during steel pipe pile penetration is the primary reason for the lower bearing capacity of steel pipe piles in coral reef limestone stratums. This method provides a novel approach for studying the mechanical properties of reef limestone. The findings can serve as a guide for the design and construction of steel pipe piles in the reef limestone stratum.

Study on the structure parameters and design method optimization of blade-type screw steel pipe pile

“…The ultimate bearing capacity reached the maximum when the ratio of the blade diameter to the pile diameter was 3.3. Chunyu Han [1] made screw pile specimens (the steel pipe wall thickness is the same as the blade thickness) by using steel pipes of given diameters and blades of different diameters. Through the sandbox test, it was concluded that the bearing capacity of a single pile gradually increased with the increasing ratio of blade diameter D to steel pipe diameter R, but the increasing trend of bearing capacity of the single pile receded when D/R was over 4.…”

“…Literature [1] analyzed the effect of D/R on the bearing capacity of a single pile using sandbox tests and finite element software ABAQUS under the premise of constant t0, and concluded that the stress range on the blade was wider when the D/R ratio was 1.5～3 (i.e. a=0.5～2).…”

“…Blade-type screw steel pipe pile is a kind of special-shaped pile with a complex geometric surface, which is composed of a steel pipe pile and several helical blades (see Fig1, hereafter referred to as "screw pile"). Besides such advantages as standardized production, industrialized construction and environment-friendliness, screw piles are of good economic efficiency, as well as high compression and uplift resistance, which are widely used in power transmission and transformation, photovoltaic and slope support projects [1,2] . With its expanding application field in recent years, screw piles boast an increasingly extensive presence in civil construction, bridge foundation, roadbed construction, building foundation reinforcement and other projects [3] .…”

Soil Consolidation Analysis in the Context of Intermediate Foundation as a New Material Perspective in the Calibration of Numerical–Material Models

“…The columns in the FEA analysis were modeled as volume pile elements with an interface at the nearside [28]. For each of the three steps of forced displacement of the plate, i.e., s = 0.01D, 0.03D, and 0.08D, the distribution of axial force, as well as friction at the lateral along the column, was read (Figures 14-17).…”

Influence of Load–Settlement Relationship of Intermediate Foundation Pile Group on Numerical Analysis of a Skyscraper under Construction

“…The use of an indirect foundation on piles in such a situation means that the resistance of the soil mobilised under the pond will be ignored. Therefore, when ground conditions allow it, i.e., the subsoil is sufficiently low deformation and, at least to a limited extent, load-bearing, it is possible to analyse the inclusion of soil under the pond, i.e., to combine a direct foundation with a deep foundation in order to mobilise both types of foundations simultaneously [2]. Such a combination of two foundation methods is popularly referred to in the literature as a combined pile-raft foundation-CPRF.…”