Self-similar solutions provide good descriptions for the gravitational collapse of spherical clouds or stars when the gas obeys a polytropic equation of state, p = Kργ (with γ ≤ 4/3, and γ = 1 corresponds to isothermal gas). We study the behaviors of nonradial (nonspherical) perturbations in the similarity solutions of Larson, Penston and Yahil, which describe the evolution of the collapsing cl...

Most slope collapse accidents are indicated by certain signs before their occurrence, and unnecessary losses can be avoided predicting deformation. However, the early warning of deformation often misjudged. It is necessary to establish a method determine appropriate in sliding thresholds. Here, better understand impact different scales on thresholds, we used Fisher optimal segmentation threshol...

The influence of the matrix material on the deformation and failure mechanisms in metal matrix syntactic foams was investigated in this study. Samples with commercially pure Al (Al) and Al-12 wt % Si (AlSi12) eutectic aluminum matrix, reinforced by hollow ceramic spheres, were compressed at room temperature. Concurrently, the acoustic emission response and the strain field development on the su...

We study a notion of deformation for simplicial trees with group actions (G{ trees). Here G is a xed, arbitrary group. Two G{trees are related by a deformation if there is a nite sequence of collapse and expansion moves joining them. We show that this relation on the set of G{trees has several characterizations, in terms of dynamics, coarse geometry, and length functions. Next we study the defo...

Artificial water pumping and rainfall will induce groundwater level fluctuations, leading to large-scale karst collapse. Therefore, the combination of physical model test FLAC3D numerical simulation is adopted simulate soil cave collapse caused by three different initial fluctuations in this paper. The influence various heights on variation water-gas pressure, pressure overlying layer, deformat...

This paper highlights the effects of cell wall material strain hardening and density functional gradation (FG) on in-plane constant-velocity dynamic crushing response and impact behavior of hexagonal honeycombs. Results show that cell wall material strain hardening influences the distinct deformation modes induced by crushing velocity generally observed in regular hexagonal honeycombs. This is ...

Abstract Shield tunneling and construction in sandy soil have great safety risks, so it is necessary to study the disturbance caused by soil. However, law of still relatively vague, this paper relies on actual tunnel project, through high-density, close monitoring; The settlement around shield studied analyzed. research shows that basically stable after tail leaves monitoring section about twic...