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The strength deterioration of compacted loess caused by drying–wetting cycles is influenced by various factors. In this paper, the influence of dry density (ρ), drying–wetting amplitude (A), and lower bounds of drying–wetting cycles (wl) on strength deterioration of compacted loess due to drying–wetting cycles was studied through triaxial tests and environmental scanning electron microscope (ESEM). By fitting a hyperbolic function to the deterioration data, the influence of ρ, A, and wl on the maximum deterioration rate and the development speed of the deterioration of strength parameters were quantitatively analyzed. Accordingly, a compacted loess deterioration model (CLDM) that comprehensively considers the influencing factors was established. Finally, based on Python, the CLDM was applied to finite element software ABAQUS, and the stability of a loess fill slope after exposure to drying–wetting cycles was analyzed. Analysis results show that the CLDM is capable of simulating the effect of drying–wetting cycles on the stability of fill slopes. [ABSTRACT FROM AUTHOR]

To define the deformation of time and space during the construction of a long and deep foundation pit in collapsible loess, the field-measured data of 10 open excavation stations in Xi'an metro are analyzed statistically. The results indicate that the vertical deformation of the ground and the lateral deformation of the soldier pile caused by the excavation of a long and deep foundation pit in collapsible loess increase with time. The maximum surface subsidence decreases with the increase in stiffness (K) of the foundation pit support system, increases linearly with the excavation depth (Hw), and decreases with the increase in the aspect ratio of the foundation pit. The lateral maximum deformation value of the soldier pile decreases linearly with the increase in insertion ratio and decreases with the increase in K of the support system. The surface subsidence of the foundation pit is characterized by a "groove shape", and the deformation of the soldier pile is characterized as the "medium convex". These results can provide a reference for the design and construction of similar projects in loess areas, and can predict and evaluate the deformation size and safety of similar projects, which is of great significance for further understanding the deformation mechanism of deep foundation pits in loess areas, thus perfecting the design theory and preventing foundation pit accidents. [ABSTRACT FROM AUTHOR]

The gravity increase method (GIM) has an inherent defect that may result in an incorrectly calculated safety factor or result in a failure to obtain the expected outcome. In this study, the error source of the GIM was quantitatively analyzed through theoretical derivation to address this problem. Hence, the modified gravity increase method (MGIM), which can eliminate the error in the GIM, was developed by adding a correction factor to the friction angle during the gravity increase procedure. The MGIM was comparatively studied by applying the GIM, shear strength reduction method (SSR), and MGIM to homogeneous slope models under different dimensions, and an ACADS (Australian Computer Aided Design Society) test was introduced to validate the applicability of the MGIM to heterogeneous slopes. The analysis results proved that the MGIM does not have the inherent defect present in the GIM, and can provide accurate results in the stability analysis of both homogeneous slope and heterogeneous slopes with various slope angle and slope height. Finally, the MGIM and GIM were applied to the numerical analysis of a geotechnical centrifugal model test of a soil slope. The results indicate that the MGIM is capable of capturing the deformation and failure characteristic of geotechnical centrifugal model test of soil slopes. [ABSTRACT FROM AUTHOR]

The general contracting projects are developed in China, in the past two decades. In the early stage of a project, because of the lack of specific design drawings and project plans, it is difficult for the general contractor to determine the construction period when signing the contract. However, little research has undertaken on quickly and efficiently estimating construction duration of a general contracting industrial project. Therefore, the purpose of this paper is to explore a suitable model for estimating construction duration of the general contracting industrial project in China. Data for 90 completed projects are collected in a company that undertakes nationwide industrial projects. Four single variable models and fourteen multivariate models are analyzed using statistical method. And the residual modified model integrating wavelet neural network (WNN) is also developed through using a predictive error to amend the statistical model. The results show that the residual modified models obtain more enhanced prediction accuracy than regression models, despite their good fitting performance. The modified model can be used for helping contractors forecast project duration in the early stage of a project. [ABSTRACT FROM AUTHOR]

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