Model Tests of Soil Reinforcement Inside the Bucket Foundation with Vacuum Electroosmosis Method

Abstract

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.

Rational Engineering of Multilayered Co3O4/ZnO Nanocatalysts through Chemical Transformations from Matryoshka‐Type ZIFs

“…We have also prepared core–shell structured ZIF‐67@ZIF‐8 by using ZIF‐67 as the core . Then, the two‐layer ZIF‐67@ZIF‐8 was calcined at different temperatures in the air (e.g., 300 °C, 360 °C, 400 °C, 800 °C), and the morphology of the ZIF‐67@ZIF‐8 after calcination were systematically analyzed by EDX elemental maps ( Figure a–d).…”

“…Preparation of Matryoshka‐Type (ZIFs@) n−1 ZIFs : For the preparation of multilayered ZIFs, ZIF‐67 nanocubes were used as the innermost core. Then ZIF‐8 and ZIF‐67 layers were grown alternately in the radial direction by a stepwise liquid phase epitaxial growth method.…”

“…Recently, our group has reported a perfect combination method to integrate two isomorphic ZIFs (i.e., ZIF‐8 and ZIF‐67) to construct a Matryoshka‐type (ZIFs@) n −1 ZIFs by multiple heteroepitaxial growths . In the present contribution, we intend to utilize the Matryoshka‐type (ZIFs@) n −1 ZIFs with tailorable layers as solid precursors to prepare ZDMOs via a facile calcination method, as shown in Scheme .…”

Synthesis of Copper‐Substituted CoS2@CuxS Double‐Shelled Nanoboxes by Sequential Ion Exchange for Efficient Sodium Storage

“…Transmission electron microscopy (TEM) images further revealed their solid nature and smooth surface (Figure d; see also Figure S1 c). Given that ZIF‐67 and ZIF‐8 are isostructural, a well‐defined core–shell ZIF‐67@ZIF‐8 composite can be formed through a seeded epitaxial growth process. The obtained ZIF‐67 and ZIF‐67@ZIF‐8 showed similar X‐ray diffraction (XRD) patterns (see Figure S2), and energy‐dispersive X‐ray spectroscopy (EDX) analysis (see Figure S3) confirmed the presence of the element Zn in the obtained product after the seeded epitaxial growth process.…”

Concrete Support Structures for Offshore Wind Turbines: Current Status, Challenges, and Future Trends

“…Construction and installation of two wind turbines with composite bucket foundations at the Dafeng wind farm, in the Sanxia Dafeng Sea, Jiangsu, China: (a) onshore prefabrication, (b) transportation and (c) installation using a dedicated vessel. Reproduced from[110], licensed under CC-BY 4.0.…”