Salt-rich soft soils have not only general characteristics of common soft soils, but also contain high contents of Mg2+, Cl?, and SO42?, which have negative effects on deep mixing method using cement to treat soft soils. Laboratory and field tests were conducted to investigate the effects of changing cement incorporating ratio, water content, cement mixing ratio, and contents of Mg2+, Cl?, and SO42? on the unconfined compressive strength of the salt-rich soil–cement. The microstructure of soil–cement and the mechanism for the strength change of salt-rich soil–cement were investigated using X-ray diffraction, scanning electronic microscopy (SEM), and backscattered diffraction technology. It was found that an increase of cement incorporating ratio enhanced the strength of soil–cement but reduced its strength when water is added. Different amounts of Mg2+, Cl?, and SO42? not only caused the difference in the microstructures of salt-rich soil–cement but also influenced the soil–cement strength. 相似文献
The Mohr–Coulomb, Tresca and Von Mises criteria are classical failure criteria, widely accepted and used for various materials. To take into account the influence of intermediate principal stress on the strength of soil, Bishop, Lade–Duncan and Matsuoka proposed criteria in terms of three principal stresses or three stress invariants. This note describes an expression with two parameters for modeling the shape of the failure surface in the octahedral plane. By studying the roles of these two parameters and comparing the new criterion with the aforementioned criteria, the advantage and flexibility of the proposed function is explored. Application of the function is demonstrated by fitting the new surface to experimental data for various soils. 相似文献
Hydrodynamic models have been widely used in urban flood modelling. Due to the prohibitive computational cost, most of urban flood simulations have been currently carried out at low spatial resolution or in small localised domains, leading to unreliable predictions. With the recent advance in high-performance computing technologies, GPU-accelerated hydrodynamic models are now capable of performing high-resolution simulations at a city scale. This paper presents a multi-GPU hydrodynamic model applied to reproduce a flood event in a 267.4 km2 urbanised domain in Fuzhou, Fujian Province, China. At 2 m resolution, the simulation is completed in nearly real time, demonstrating the efficiency and robustness of the model for high-resolution flood modelling. The model is used to further investigate the effects of varying spatial resolution and using localised domains on the simulation results. It is recommended that urban flood simulations should be performed at resolutions higher than 5 m and localised simulations may introduce unacceptable numerical errors.