Abstract
This paper presents a simple but workable constitutive model for the stress–strain relationship of sandy soil during the process of tunneling construction disturbance in coastal cities. The model was developed by linking the parameter K and internal angle φ of the Duncan–Chang model with the disturbed degree of sand, in which the effects of the initial void ratio on the strength deformation property of sands are considered using a unified disturbance function based on disturbed state concept theory. Three cases were analyzed to investigate the validity of the proposed constitutive model considering disturbance. After validation, the proposed constitutive model was further incorporated into a 3D finite element framework to predict the soil deformation caused by shield construction. It was found that the simulated results agreed well with the analytical solution, indicating that the developed numerical model with proposed constitutive relationship is capable of characterizing the mechanical properties of sand under tunneling construction disturbance.
Highlights
There is an ongoing demand for tunnel construction in coastal cities that need to shore up their crumbling infrastructure, seeking more efficient and less polluting modes of transportation
The disturbance of shield construction, which is one of the popular construction methods in coastal cities of China, affects the mechanical behavior of coastal sand by changing its physical properties, including the void ratio, water content and internal friction angle (φ) associated with the weakening of the initial tangent modulus (Ei ), which may lead to uneven settlement and the cracking of nearby buildings. Such a complex disturbance process can be well reproduced using disturbed state concept (DSC) theory [18,19], in which the physical and mechanical behavior of structured geo-materials at any stage during deformation under mechanical and/or environmental loadings can be expressed in terms of the behavior of material parts in the two reference states: relatively intact (RI) and fully adjusted (FA) states
A total of 24 standard undrained monotonic triaxial tests were conducted by Zhu et al [23] at a strain rate of 0.808 mm/min for dry sand, with the failure criterion being controlled by the peak strength
Summary
There is an ongoing demand for tunnel construction in coastal cities that need to shore up their crumbling infrastructure, seeking more efficient and less polluting modes of transportation. The disturbance of shield construction, which is one of the popular construction methods in coastal cities of China, affects the mechanical behavior of coastal sand by changing its physical properties, including the void ratio, water content and internal friction angle (φ) associated with the weakening of the initial tangent modulus (Ei ), which may lead to uneven settlement and the cracking of nearby buildings Such a complex disturbance process can be well reproduced using disturbed state concept (DSC) theory [18,19], in which the physical and mechanical behavior of structured geo-materials at any stage during deformation under mechanical and/or environmental loadings can be expressed in terms of the behavior of material parts in the two reference states: relatively intact (RI) and fully adjusted (FA) states. Figure construction disturbance to the mechanical propertiesproperties of coastal sand
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