Comparison between Numerical and Analytical Analysis of the Dynamic Behavior of Circular Tunnels

Dynamic behavior of underground structures is controlled by the strain field imposed by wave propagation and by the interaction between rock mass and structures. Shear and pressure waves propagating in the plane of the cross-section of the tunnel generate ground distortions, which tend to cause ovaling deformations of the lining. In this paper, the seismic response of a circular tunnel subjected respectively to shear waves and pressure waves will be analyzed both analytically and numerically at first, and then a complete 3D analysis will be given to show the overall effects on a tunnel induced by seismic events considering seismic inputs in three directions.El comportamiento dinámico de estructuras subterráneas se controla por el campo de deformación impuesta por la propagación de ondas y por la interacción entre la masa rocosa y las estructuras. La onda de cizallamiento y la onda de presión en el plano de sección transversal del túnel generan distorsiones del terreno que tienden a causar deformaciones ovaladas del revestimiento de la estructura. En este artículo se analiza la respuesta sísmica de un túnel circular sujeto respectivamente a ondas de cizallamiento y ondas de presión tanto analítica como numéricamente. Luego se muestra un análisis tridimensional completo para mostrar los efectos generales en un túnel producidos por eventos sísmicos y donde se consideran registros en tres direcciones

IRE1α promotes cell apoptosis and an inflammatory response in endoplasmic reticulum stress-induced rheumatoid arthritis fibroblast-like synovial cells by enhancing autophagy

Endoplasmic reticulum (ER) stress can induce autophagy via the unfolded protein response (UPR), and autophagy can regulate the activation of inflammasomes. Inositol-requiring enzyme 1α (IRE1α) is a transducer of the UPR in cells with ER stress. Here, we investigated the role of IRE1α and its impact on ER stress in rheumatoid arthritis fibroblast-like synovial cells (RA-FLSs). RA-FLSs were isolated from rheumatoid arthritis (RA) patients and stimulated with thapsigargin (TG) to produce ER stress cells. ER stress-, autophagy and the expression of apoptosis-associated factors were investigated by western blotting and the qRT-PCR. Cellular ROS levels were assessed by flow cytometry. ELISAs were performed to determine the concentrations of inflammatory mediators. TG treatment promoted IRE1α, GRP78, CHOP, and ATP6 mRNA and protein expression. ROS generation was increased in TG-induced RA-FLSs; additionally, TG was found to induce cell inflammation by upregulating the expression of inflammasome markers and the concentrations of inflammatory mediators. The levels of autophagy markers, apoptosis-associated proteins, and mRNA were increased in TG-stimulated RA-FLSs. However, transfection with si-IRE1α suppressed TG-induced increases in ROS generation, inflammation levels, cell apoptosis, and autophagy in RA-FLSs. Treatment with the autophagy activator RAPA attenuated the protective effects of IRE1α silencing on TG-induced RA-FLS apoptosis and inflammatory damage. Our findings showed that in RA-FLSs, IRE1α silencing alleviated ER stress-induced inflammation and apoptosis caused by autophagy

A multifunctional azobenzene-based polymeric adsorbent for effective water remediation

The efficient removal of trace carcinogenic organic pollutants, such as polycyclic aromatic hydrocarbons (PAHs) and ionic dyes, from water is an important technical challenge. We report a highly effective recyclable multifunctional azobenzene (AZ)-based silica-supported polymeric adsorbent which can simultaneously remove both PAHs and anionic dyes from water to below parts per billion (ppb) level based on multiple interactions such as the hydrophobic effect, [pi]–[pi] stacking and electrostatic interactions, thus providing a new strategy for designer water remediation materials

Seismic analysis of a large size underground cavern

Underground structures are generally assumed to be much safer to earthquake loading, compared to above surface structures. However, many large underground structures have witnessed great damage in recent earthquakes. Thus underground structures in earthquake prone zones should be designed to withstand both static overburden loads and earthquake loads. In this thesis, analytical and numerical analyses of circular tunnels subjected to different types of waves are firstly performed. Then a systematic approach for the dynamic analysis of large size underground openings such as powerhouses and hydroelectric caverns is presente

Analytical and numerical modelling of underground structures in seismic conditions

Waves propagating in the plane of the cross-section of a tunnel during seismic shaking generate ground distortions which tend to cause ovaling deformations of the lining. The resulting change in shape of the tunnel cross-section generates circumferential strains in the lining which can cause cracking and/or crushing of concrete and reduction of its carrying load capacity. In this paper, different closed form solutions for the analysis of the tunnel response are considered on the basis of the theory that the stress increment due to seismic loading can be assessed through a correct estimation of free-field deformations. Numerical analyses, in both two and three dimensional conditions, with the Finite Element Method, are performed and the comparison with analytical solutions is carried out. The uncoupled seismic response of a circular tunnel is analyzed both analytically and numerically, to investigate the seismic response of tunnels subjected only to shear or pressure waves. Then, a complete three dimensional analysis is performed to evaluate the overall response of the tunnel and the stresses induced in the lining by seismic loading. The results obtained by numerical modelling, in both two and three dimensional conditions, agree well with most of the analytical results, as long as seismic loading is applied in one direction only. When consideration is given to the three dimensional model with both horizontal and vertical motion, the numerical results agree with the analytical results based on a combination of the corresponding analytical solution

2D and 3D continuum static and dynamic modeling of a large span powerhouse cavern in Italy

Following geological and geomechanical investigations with laboratory and in-situ tests, as well as the selection of the seismic input based on past earthquake records, stability analyses of the Venaus powerhouse cavern in Italy have been performed with both static and dynamic modeling studies. 2D and 3D design analyses have been carried out in static conditions by accounting for the excavation-construction sequence, including the simulation of the reinforcement system installed. Close attention has been given to the analysis of the disturbed zone around the cavern as well as to the reinforcement system used to insure the cavern stability. Performance monitoring data of crown displacements have been taken into account for appropriate validation of the analyses performed. Performance analyses have also been carried out under seismic conditions and for selected design ground motions. The dynamic response of the surrounding rock mass and of the reinforcement system has been investigated. The results obtained are of interest in relation to future stability analyses to be performed for large underground caverns constructed in the past, based on seismic design analyses and input data derived from updated post earthquake records recently made available in Ital

Comparison between Numerical and Analytical Analysis of the Dynamic Behavior of Circular Tunnels

Dynamic behavior of underground structures is controlled by the strain field imposed by wave propagation and by the interaction between rock mass and structures. Shear and pressure waves propagating in the plane of the cross-section of the tunnel generate ground distortions, which tend to cause ovaling deformations of the lining. In this paper, the seismic response of a circular tunnel subjected respectively to shear waves and pressure waves will be analyzed both analytically and numerically at first, and then a complete 3D analysis will be given to show the overall effects on a tunnel induced by seismic events considering seismic inputs in three directions

Research on ecological water demand of lakes

With the rapid development of social economy, the development and utilization of water resources is increasing, which leads to the increasing importance of ecological water demand in wetland protection. The study of lake ecological water demand can provide theoretical basis for improving the distribution of water resources and ecosystem balance in lake wetland and establish a solid theoretical basis for the sustainable development of lake wetland ecosystem. Based on the analysis and summary of the relevant literature on wetland ecological water demand, this paper expounded the connotation of lake ecological water demandand summarized the calculation method of ecological water demand of lake type wetland in China. In addition,this paper pointed out that the research focus of lake ecological water demand mainly included the application of hydrologicalhydrodynamic- water quality and the research of water demand based on ecological protection target hydrology demand