A spatiotemporal deep learning method for excavation-induced wall deflections

Data-driven approaches such as neural networks are increasingly used for deep excavations due to the growing amount of available monitoring data in practical projects.However,most neural network models only use the data from a single monitoring point and neglect the spatial relationships between multiple monitoring points.Besides,most models lack flexibility in providing predictions for multiple days after monitoring activity.This study proposes a sequence-to-sequence(seq2seq)two-dimensional(2D)convolutional long short-term memory neural network(S2SCL2D)for predicting the spatiotemporal wall deflections induced by deep excavations.The model utilizes the data from all monitoring points on the entire wall and extracts spatiotemporal features from data by combining the 2D convolutional layers and long short-term memory(LSTM)layers.The S2SCL2D model achieves a long-term prediction of wall deflections through a recursive seq2seq structure.The excavation depth,which has a significant impact on wall deflections,is also considered using a feature fusion method.An excavation project in Hangzhou,China,is used to illustrate the proposed model.The results demonstrate that the S2SCL2D model has superior prediction accuracy and robustness than that of the LSTM and S2SCL1D(one-dimensional)models.The prediction model demonstrates a strong generalizability when applied to an adjacent excavation.Based on the long-term prediction results,practitioners can plan and allocate resources in advance to address the potential engineering issues.

An approach for determination of lateral limit angle in kinematic planar sliding analysis for rock slopes

Planar sliding is one of the frequently observed types of failure in rock slopes.Kinematic analysis is a classic and widely used method to examine the potential failure modes in rock masses.The accuracy of planar sliding kinematic analysis is significantly influenced by the value assigned to the lateral limit angleγlim.However,the assignment ofγlim is currently used generally based on an empirical criterion.This study aims to propose an approach for determining the value ofγlim in deterministic and probabilistic kinematic planar sliding analysis.A new perspective is presented to reveal thatγlim essentially influences the probability of forming a potential planar sliding block.The procedure to calculate this probability is introduced using the block theory method.It is found that the probability is correlated with the number of discontinuity sets presented in rock masses.Thus,different values ofγlim for rock masses with different sets of discontinuities are recommended in both probabilistic and deterministic planar sliding kinematic analyses;whereas a fixed value ofγlim is commonly assigned to different types of rock masses in traditional method.Finally,an engineering case was used to compare the proposed and traditional kinematic analysis methods.The error rates of the traditional method vary from 45%to 119%,while that of the proposed method ranges between 1%and 17%.Therefore,it is likely that the proposed method is superior to the traditional one.

A universal elliptical disc(UED)model to represent natural rock fractures

Since natural fractures are often non-equidimensional,the circular disc model still has great limitations.By contrast,the elliptical disc model is more applicable to representing natural fractures,especially for slender ones.This paper developed a universal elliptical disc(UED)model by incorporating the center point,size,and azimuth of fractures as variables.Specifically,with respect to the azimuth of elliptical fractures in three-dimensional(3D)space,we proposed a paradigm to construct its probability density function(PDF)by coupling the orientation and rotation angle of long axis based on three coordinate transformations.To illustrate the construction process of the PDF of the fracture azimuth,we took the orientation following the Fisher distribution and the rotation angle following Von Mises distribution as an example.A rock slope is used to show the use of the developed UED model,and the 3D DFNs for the slope rock mass are generated by Monte Carlo simulation.In addition,the DFNs for the rock mass are also generated based on the existing circular disc model and non-universal elliptical disc model.The comparison results from the three models clearly illustrate the superiority of the UED model over the existing circular and non-universal elliptical disc models.

H3亚型禽流感流行的潜在危害和防控建议

21世纪短短的20年间,人类已经历了两次大流行传染病,即2009年甲型H1N1大流行流感和2019年新型冠状病毒感染.另外发生了5次世界卫生组织宣布的“全球关注的公共卫生应急事件”,给全球经济发展、社会稳定和人类健康造成了严重危害(https://www.who.int/emergencies/situations).大流行传染病的频繁出现警示我们,人兽共患性病毒是引发大流行疫病的重要病原.动物源性流感病毒在历史上导致了至少5次流感大流行,尤其是最近几年,动物流感病毒频繁跨种感染人类的现象让人们担忧其可能催生下一次人类流感大流行[1].

Monotonic uplift behavior of anchored pier foundations in soil overlying rock

Rock-embedded foundations with good uplift and bearing capacity are often used in mountains or hilly areas.However,there are soil layers with a certain thickness on the rocks in these mountainous areas,and the utilization of those soil layers is a problem worthy of attention in foundation construction.Considering construction-and cost-related factors,traditional single-form foundations built on such sites often cannot provide sufficient resistance against uplift.Therefore,an anchored pier foundation composed of anchors and belled piers,specifically constructed for such conditions,can be invaluable in practice.This paper introduces an experimental and analytical study to investigate the uplift capacity and the uplift mobilization coefficients(UMCs)of the anchored pier foundation.In this study,three in-situ monotonic pullout tests were carried out to analyze the load–displacement characteristics,axial force distribution,load transfer mechanism,and failure mechanism.A hyperbolic model is used to fit the load–displacement curves and to reveal the asynchrony of the ultimate limit states(ULSs)of the anchor group and the belled pier.Based on the results,the uplift capacity can be calculated by the UMCs and the anchor group and pier uplift capacities.Finally,combined with the estimation of the deformation modulus of the soil and rock,the verification calculation of the uplift capacity and UMC was carried out on the test results from different anchored pier foundations.

Multi-objective optimization-based prediction of excavation-induced tunnel displacement

This paper proposes an inverse method for improving the prediction of tunnel displacements during adjacent excavation.In this framework,staged data assimilation and parameter identification are conducted using the multi-objective particle swarm optimization algorithm.Recent monitoring data are assumed to be more informative and assigned more weights in the multi-objective optimization to improve the prediction accuracy.Then,an empirical formula is applied to correct the time effect of tunnel displacement.The Kriging method is introduced to surrogate the finite element model to reduce computational cost.The proposed framework is verified using a typical staged“excavation nearing tunnel”case.The predictions using the updated parameters are in good agreement with the measurements.The identified values of underlying soil parameters are within the typical ranges for the unloading condition.The updated time effect indicates that tunnel displacements may develop excessively in the three months after the region S1-B is excavated to the bottom.The maximum vertical tunnel displacement may increase from the currently measured 12 mm to the calculated 26 mm if the later construction is suspended long enough.Subsequent constructions need to be timely conducted to restrain the time effect and control tunnel displacements.

Functional divergence of oligoadenylate synthetase 1(OAS1)proteins in Tetrapods

OASs play critical roles in immune response against virus infection by polymerizing ATP into 2-5 As,which initiate the classical OAS/RNase L pathway and induce degradation of viral RNA.OAS members are functionally diverged in four known innate immune pathways(OAS/RNase L,OASL/IRF7,OASL/RIG-I,and OASL/cGAS),but how they functionally diverged is unclear.Here,we focus on evolutionary patterns and explore the link between evolutionary processes and functional divergence of Tetrapod OAS1.We show that Palaeognathae and Primate OAS1 genes are conserved in genomic and protein structures but differ in function.The former(i.e.,ostrich)efficiently synthesized long 2-5 A and activated RNase L,while the latter(i.e.,human)synthesized short 2-5 A and did not activate RNase L.We predicted and verified that two in-frame indels and one positively selected site in the active site pocket contributed to the functional divergence of Palaeognathae and Primate OAS1.Moreover,we discovered and validated that an in-frame indel in the C-terminus of Palaeognathae OAS1 affected the binding affinity of ds RNA and enzymatic activity,and contributed to the functional divergence of Palaeognathae OAS1 proteins.Our findings unravel the molecular mechanism for functional divergence and give insights into the emergence of novel functions in Tetrapod OAS1.

Effects of RNA interference targeting angiotensin 1a receptor on blood pressure and cardiac hypertrophy of rats with renovascular hypertension

The aim of this study is to investigate the effects of RNA interference(RNAi)targeting angiotensin 1a receptor(AT1a)on blood pressure and cardiac hypertrophy of rats with renovascular hypertension.Two RNAi plasmids,pAT1a-shRNA1 and pAT1ashRNA2 each carrying a U6 promoter and an AT1aspecific shRNA-coding template sequence corresponding to the sites 928-946,978-996 of the mRNA transcript,and a control plasmid pCon carrying a nonspecific shRNA-coding sequence were constructed.Thirty Sprague-Dawley rats with renovascular hypertension(2-kidney 1-clip)were randomly divided into 5 equal groups:Control group(without any intervention),pAT1a-shRNA1,pAT1a-shRNA2,pCon groups(with injection of the corresponding plasmid 4 mg/kg respectively into the tail vein),and valsartan group(30 mg/kg·d^(-1) by gavage).Three weeks after drug administration,pAT1a-shRNA1,pAT1a-shRNA2 and valsartan respectively resulted in decrease of the tail blood pressure by(15.1±5.4),(16.4±8.4)and(30.6±18.2)mmHg.However,the tail blood pressure increased further by about 25 mmHg in both of pCon and control groups.The carotid artery pressures of pAT1a-shRNA1,pAT1ashRNA2 and valsartan groups were all significantly lower than those of the control and pCon groups.The ratio of left ventricle weight to body weight(LV/BW)of the rats in pAT1a-shRNA1,pAT1a-shRNA2,and valsartan groups decreased significantly than in the control group(P<0.01),similar to those of the normal SD rats(P>0.05).Histopathological examination showed that the myocardiocytes were significantly hypertrophic and the basal membrane of the aorta was significantly thickened in the control group and such changes were alleviated in the pAT1a-shRNA1,pAT1a-shRNA2 and valsartan groups.Compared with the control group,pAT1a-shRNA1 and pAT1a-shRNA2 groups had lowered expression of AT1 receptor(in the myocardium and the thoracic aorta(all P<0.01);however,there were no significant differences in expression levels of AT1 receptor in valsartan and the control groups(P>0.05).We conclude that RNAi targeting AT1a receptor inhibits the development of renovascular hypertension and the accompanying cardiac hypertrophy.RNAi technology may become a new strategy of gene therapy for hypertension.

Assessment of vaccination strategies against highly pathogenic avian influenza in China

Vaccination for highly pathogenic avian influenza(HPAI)has been implemented in China for a decade,however,the virus is still present in poultry.A series of recombinant vaccines,Re-1 to Re-7,have been developed and used,and Re-8 will also be used in clinical settings to prevent the prevailing flu strains.The question remains,when can China eradicate the disease?Here,we review the epidemiology of H5 HPAI along with the development,usage and problems of vaccines.Further suggestions for controlling the disease in China are provided.