Search Results (3)

In this study, we introduced a new type of basis function and subsequently a Chebyshev delta shaped collocation method (CDSC). We then use this method to numerically investigate both the natural convective flow and heat transfer of nanofluids in a vertical rectangular duct on the basis of a Darcy–Brinkman–Forchheimer model and the electroosmosis-modulated Darcy–Forchheimer flow of Casson nanofluid over stretching sheets with Newtonian heating problems. The approximate solution is represented in terms of Chebyshev delta shaped basis functions. Novel error estimates for interpolating polynomials are derived. Computational experiments were carried out to corroborate the theoretical results and to compare the present method with the existing Chebyshev pseudospectral method. To demonstrate our proposed approach, we also compared the numerical solutions with analytic solutions of the Poisson equation. Computer simulations show that the proposed method is computationally cheap, fast, and spectrally accurate and more importantly the obtained approximate solution can easily be used by researchers in this field. Full article

A vertical electro-osmosis method was proposed to improve the bearing capacity of piles in marine soft clay foundations. A top-down electro-osmosis test was conducted by setting an anode and cathode at the top and bottom of the pile, respectively, while the settings of bottom-up electro-osmosis were set in the opposite way. At the same time, a pile without electro-osmosis was also set up for comparison. The variation law of water content, water discharge volume, soil pressure, and surface settlement of soil around the pile during electro-osmosis was tested and analyzed. A direct shear test and static load test were carried out to study the effects of vertical electro-osmosis on the shear strength of soil and the bearing capacity of the pile. The experimental results show that vertical electro-osmosis can significantly improve the bearing capacity of the pile and the shear strength of soil around the pile. The bearing capacity of the piles in the top-down electro-osmosis test was 16.7% higher than that in the bottom-up electro-osmosis test, and the amount of water discharged was 41.69% higher. Compared with the horizontal electro-osmosis around the pile, the vertical electro-osmosis had a faster drainage speed, better soil consolidation, and a slightly smaller increase in the bearing capacity of the pile. Because vertical electro-osmosis is easy to implement on concrete piles, the new method proposed in this study has a broad application prospect. Full article

Offshore wind turbine foundations are commonly subjected to large horizontal, vertical, and bending moment loads. Marine soils have high moisture content, high compressibility, high sensitivity, and low strength, resulting in insufficient foundation bearing capacity. In order to improve the bearing capacity of wind turbine foundations and reduce foundation settlement, an internal vacuum preloading method combined with electroosmosis reinforcement is used to reinforce the soil within bucket foundations. The pore water pressure, vertical settlement, pumping quality of the soil during the reinforcement process, soil moisture content before and after the reinforcement, and undrained shear strength were analyzed. Horizontal and vertical bearing capacity model tests were carried out on the reinforced and nonreinforced soil inside the bucket foundation. Results show that vacuum preloading combined with electroosmosis reinforcement reduces soil moisture content inside the bucket foundation by approximately 20%, and the undrained shear strength of the internal soil increases by approximately 20 times. Soil reinforcement has high spatial uniformity. Results of the bucket foundation bearing capacity model show that when the soil inside the bucket foundation is strengthened, horizontal bearing capacity increased by 2.9 times and vertical bearing capacity increased by 2.1 times. Vacuum preloading combined with electroosmosis reinforcement can effectively improve the shear strength of soft soil and enhance the bearing capacity and stability of bucket foundations. Full article