Experimental study on out-of-plane seismic performance of precast composite sidewalls of utility tunnel with grouting-sleeve joints

The precast composite reinforced concrete wall with the advantages of fewer joints,superior impermeability and rapid construction provides an efficient and environmental friendly alternative in the construction of underground utility tunnels in the last few years.To investigate the seismic performance of precast concrete composite walls of utility tunnels with grouting-sleeve connection under out-ofplane loads,a series of quasi-static cyclic tests were performed on the full-scale sidewall specimens with different axial compression ratios in this study.The experimental results including the failure modes,crack distributions,and the influence of different connections on the out-of-plane seismic performance of precast concrete composite wall were carefully examined and compared with those from the cyclic tests of the cast-in-place sidewalls of the utility tunnel.The test results show that the seismic performance of the precast concrete composite sidewall specimen,such as the hysteresis curves,the ultimate bearing capacity,stiffness degradation pattern and the ductility ratio,is basically the same as that of the cast-in-place specimen,indicating that the seismic performance of the prefabricated structure is equivalent to that of the cast-in-place structure.Moreover,the grouting-sleeves of the joints can effectively transfer the reinforcement stress until the failure of the precast concrete composite sidewall specimens,which exhibits excellent out-of-plane ductility and serviceability.

Seismic and vibration control of segmented isolation layer in underground structure-diaphragm wall system

In this paper,a seismic and vibration reduction measure of subway station is developed by setting a segmented isolation layer between the sidewall of structure and the diaphragm wall.The segmented isolation layer consists of a rigid layer and a flexible layer.The rigid layer is installed at the joint section between the structural sidewall and slab,and the flexible layer is installed at the remaining sections.A diaphragm wall-segmented isolation layer-subway station structure system is constructed.Seismic and vibration control performance of the diaphragm wall-segmented isolation layer-subway station structure system is evaluated by the detailed numerical analysis.Firstly,a three-dimensional nonlinear time-history analysis is carried out to study the seismic response of the station structure by considering the effect of different earthquake motions and stiffness of segmented isolation layer.Subsequently,the vibration response of site under training loading is also studied by considering the influence of different train velocities and stiffness of the segmented isolation layer.Numerical results demonstrate that the diaphragm wall-segmented isolation layer-subway station structure system can not only effectively reduce the lateral deformation of station structure,but also reduce the tensile damage of the roof slab.On the other hand,the developed reduction measure can also significantly reduce the vertical peak displacements of site under training loading.

Molecular Characterization and Expression Analysis of Matrix Metalloproteinase 3 in the Asian Yellow Pond Turtle Mauremys mutica

Matrix metallopeptidase 3 is a zinc-containing proteinase that participates in tissue remodeling and immune responses. In this study, a cDNA encoding matrix metallopeptidase 3 was isolated and characterized from the Asian yellow pond turtle Mauremys mutica（designated as MaMMP3）. The MaMMP3 cDNA is 1805 bp and consists of a 5＇-untranslated region（UTR） of 56 bp, a 3＇-UTR of 243 bp, and an open reading frame（ORF） of 1506 bp encoding 481 amino acids. Homology analysis of MaMMP3 revealed that the MaMMP3 shared 25%–63% similarity to other known MMP3 sequences. The genomic sequence covers 6007 bp. Comparative analysis of the cDNA sequence revealed that the Asian yellow pond turtle MMP3 has eight exons and seven introns. The phylogenetic tree showed that the MaMMP3 is closely related to Gallus gallus MMP3 and Taeniopygia guttata MMP3. The mRNA expression of the MaMMP3 in normal group without any bacterial challenge could be detected in all studied tissues including kidney, heart, live and spleen, with the highest level in the spleen. The results of immune challenge showed that the expression level of MaMMP3 was up-regulated in the spleen and liver. These results provided an important information for studying the roles of Asian yellow pond turtle MMP3 in immunity further.

Nonlinear Response of Tunnel Portal under Earthquake Waves with Different Vibration Directions

Tunnel portal sections often suffer serious damage in strong earthquake events.Earthquake waves may propagate in different directions,producing various dynamic responses in the tunnel portal.Based on the Galongla tunnel,which is located in a seismic region of China,three-dimensional seismic analysis is conducted to investigate the dynamic response of a tunnel portal subjected to earthquake waves with different vibration directions.In order to simulate the mechanic behavior of slope rock effectively,an elastoplastic damage model is adopted and applied to ABAQUS software by a self-compiled user material(UMAT)subroutine.Moreover,the seismic wave input method for tunnel portal is established to realize the seismic input under vertically incident earthquake waves with different vibration directions,e.g.,S waves with a vibration direction perpendicular or parallel to the tunnel axis and P waves with a vibration direction perpendicular to the tunnel axis.The numerical results indicate that the seismic response and damage mechanisms of the tunnel portal section are related to the vibration direction of the earthquake waves.For vertically incident S waves running perpendicular to the tunnel axis,the hoop tensile strain at the spandrel and arch foot and the hoop shear strain at the vault and arch bottom are the main contributors to the plastic damage of the tunnel.The strain is initially concentrated around the tunnel foot and spandrel,before shifting to the tunnel vault and bottom farther away from the tunnel entrance.For vertically incident S waves running parallel to the tunnel axis,very large hoop shear strain and plastic damage appear at the tunnel haunches.This strain first increases and then decreases with distance from the tunnel entrance.For vertically incident P waves running perpendicular to the tunnel axis,the maximum damage factor of the slope rock and the maximum plastic strain of the tunnel are significantly lower than for S waves.Moreover,with increasing distance from the tunnel entrance,the plastic damage to the tunnel lining rapidly decreases.

全过程造价在棚户区项目管理中存在问题初探

论文以中国空港经济区大板桥集镇棚户区改造(B片区)为案例,从全过程造价管理在项目建设阶段和项目实施阶段存在的问题进行分析与探讨,针对具体问题采用相对性的措施,在类似工程全过程造价管理中提供参考。

Fluorine-thiol displacement probes for acetaminophen's hepatotoxicity

Chemicals possessing reactive electrophiles can denature innate proteins leading to undesired toxicity,and the overdose-induced liver injury by drugs containing electrophiles has been one of the major causes of non-approval and withdraw by the US Food and Drug Administration(FDA).Elucidating the associated proteins could guide the future development of therapeutics to circumvent these drugs’toxicities,but was largely limited by the current probing tools due to the steric hindrance of chemical tags including the common“click chemistry”labels.Taking the widely used non-steroidal anti-inflammatory drug acetaminophen(APAP)as an example,we hereby designed and synthesized an APAP analogue using fluorine as a steric-free label.Cell toxicity studies indicated our analogue has similar activity to the parent drug.This analogue was applied to the mouse hepatocellular proteome together with the corresponding desthiobiotinSH probe for subsequent fluorine-thiol displacement reactions(FTDRs).This set of probes has enabled the labeling and pull-down of hepatocellular target proteins of the APAP metabolite as validated by Western blotting.Our preliminary validation results supported the interaction of APAP with the thioredoxin protein,which is an important redox protein for normal liver function.These results demonstrated that our probes confer minimal steric perturbation and mimic the compounds of interest,allowing for global profiling of interacting proteins.The fluorine-thiol displacement probing system could emerge as a powerful tool to enable the investigation of drug-protein interactions in complex biological environments.

On China＇ s Reform of Delay Retirement Scheme ——based on the research of American

American is one of the earliest countries that formulated the social security law. In the background of an aging population, American gradually increase the American normal retirement age, and established a delay retirement subsidy system. On the basis USA delay retirement age experience, combined with China＇s unique national conditions, to analysis China＇s current retirement system, and put forward relevant proposals for delay retirement scheme.

浅析无负压供水系统在城市轨道交通项目中应用

论文以具体工程为案例,结合轨道交通用水量小、安全性要求高的特点,对无负压供水系统与传统二次供水系统的进行比较论述,与同专业的同仁们进行分享和借鉴。

Nonlinear Seismic Response of Rock Tunnels Crossing Inactive Fault under Obliquely Incident Seismic P Waves

The failure mechanism of tunnels crossing faults is a critical issue for tunnels located in seismically active regions. This study aims to investigate the nonlinear response of rock tunnels crossing inactive faults under obliquely incident seismic P waves. Based on the equivalent nodal force method together with the viscous-spring boundary, an incident method for the site, which contains fault and is subjected to obliquely incident seismic P waves, is developed first. Then, based on the proposed incident method, the nonlinear response and the failure process of the tunnel crossing inactive fault are numerically studied. The numerical results show that the failure mechanism of the tunnel crossing inactive fault can be attributed to the combined action of the seismic waves and its associated fault slippage. Finally, parameter studies are conducted to investigate the effects of the wave impedance ratio of the fault to the surrounding rock and the incident angle of P waves. By the parameter analysis, it can be concluded that:(1) with decreasing the wave impedance ratio of the fault to the surrounding rock, the seismic response of the tunnel increases significantly;(2) the seismic response of the tunnel increases first and then decreases with the increasing of the incident angle of P waves. This study offers the insight for further research on the seismic stability of tunnels crossing inactive faults.

Analytical solution for earthquake induced hydrodynamic pressure on a circular cylinder in a two-layer fluid

The analytical method is adopted to investigate the earthquake-induced hydrodynamic pressure on a circular cylinder surrounded by a two-layer fluid.Based on the radiation theory,the analytical expressions of the hydrodynamic pressure and the hydrodynamic force on a rigid circular cylinder are obtained.Then,the dispersion relation for the radiation problem in a two-layer fluid,and the added mass and the damping coefficients on the circular cylinder are analyzed.The earthquake-induced hydrodynamic forces on the circular cylinder in a two-layer fluid are furtherly investigated.It is founded that the hydrodynamic pressures on the circular cylinder include not only the surface-wave and perturbing wave modes,but also the internal-wave mode.This is quite different from the case in a single-layer fluid.However,the results indicate that the internal-wave mode has little influence on the hydrodynamic forces on the circular cylinder in a two-layer fluid.Lastly,the seismic responses of the flexible cylinder in single-layer and two-layer fluids are studied.Some examples show that the seismic responses of the cylinder in a two-layer fluid are much larger than those in a single-layer fluid.