161 research outputs found

    Tunnelling effects on framed buildings

    Get PDF
    The ever-increasing population in the urban environment requires continuous improvement for infrastructure, which often involves tunnel construction. To predict/mitigate tunnelling-induced damage of nearby structures, for instance, surface buildings, engineers need to be able to understand the complex soil-structure interaction mechanisms caused by excavation. Nevertheless, due to the complexity of the problem, simplifications have to be made; for instance, the frequent use of an equivalent isotropic plate to represent the surface structure, which brings a high level of uncertainty within risk assessments. This dissertation investigates the response of framed buildings with shallow foundations (rafts or separate strip footings) to tunnelling through using data obtained from 44 plane-strain geotechnical centrifuge tests. The research considered 8 elastic framed building models with varying configuration, with tunnelling- and structure-related parameters also varied during tests. The response of the frames on raft foundations was contrasted against results obtained using an equivalent isotropic plate. Results indicate that, in contrast to equivalent isotropic plates, framed buildings primarily exhibit shear behaviour and a semi-flexible response with both sagging and hogging deformation modes. Regardless of the foundation configuration, buildings with a greater width (transverse to the tunnel) showed increased structural distortions, whereas building eccentricity reduced deformations because of the freedom to tilt. Tunnels with a greater cover depth resulted in a lower level of building distortion. The structure self-weight and stiffness also played a role, particularly in relation to the formation of a gap beneath the building. The relative density of sand determined the soil shear and volumetric behaviour, resulting in a greater structural deformation in loose sand than in dense sand for a given tunnel volume loss; whereas for a similar soil volume loss (equal volume of surface settlement trough), a lower level of distortion was obtained in loose sand than in dense sand, particularly for separate footings. On the other hand, the foundation configuration plays an important role in determining the ground response to tunnelling, affecting soil displacement fields as well as the distribution of soil shear and volumetric strains. Furthermore, foundation settlements and differential horizontal displacements are experimentally confirmed to be larger for separate footings compared to raft foundations. The results also highlighted the role of footing embedment on soil-foundation interaction, with the potential of causing greater horizontal displacements and strains between footings. The obtained building deformed shapes indicate that angular/shear distortions within each bay or panel are more appropriate for quantifying framed building distortions than deflection ratios. Based on this, a relative stiffness parameter is suggested to relate maximum angular distortions to the slope of the greenfield settlement profile. Linear trends of angular distortion modification factors with relative soil-building shear stiffness were observed (in semi-logscale), and for buildings with similar values of relative stiffness, the level of distortion within framed buildings is lower for separate footings than raft foundations. Upper and lower empirical envelopes for preliminary damage assessment considering building eccentricity and foundation configuration are suggested. In addition, the efficiency of available relative stiffness parameters for the deflection ratio modification factors is confirmed. Finally, limitations of the equivalent plate approach and practical implications of the results for framed buildings are discussed

    Exploiting Behavioral Consistence for Universal User Representation

    Full text link
    User modeling is critical for developing personalized services in industry. A common way for user modeling is to learn user representations that can be distinguished by their interests or preferences. In this work, we focus on developing universal user representation model. The obtained universal representations are expected to contain rich information, and be applicable to various downstream applications without further modifications (e.g., user preference prediction and user profiling). Accordingly, we can be free from the heavy work of training task-specific models for every downstream task as in previous works. In specific, we propose Self-supervised User Modeling Network (SUMN) to encode behavior data into the universal representation. It includes two key components. The first one is a new learning objective, which guides the model to fully identify and preserve valuable user information under a self-supervised learning framework. The other one is a multi-hop aggregation layer, which benefits the model capacity in aggregating diverse behaviors. Extensive experiments on benchmark datasets show that our approach can outperform state-of-the-art unsupervised representation methods, and even compete with supervised ones.Comment: Preprint of accepted AAAI2021 pape

    Role of Footing Embedment on Tunnel–Foundation Interaction

    Get PDF
    This technical note investigates the effect of footing embedment depth on tunnel-structure interaction using geotechnical centrifuge testing. A two-story framed building on separate footings, either resting directly on the surface or embedded in the soil, and subjected to tunneling induced displacements is modeled. Measurements of the displacements of the footings and underlying soil, ground deformations, and structural distortions are presented. Results show that footing embedment increases foundation differential settlements and horizontal displacements, thereby causing a greater level of distortion within the frame. Furthermore, the embedded footings result in a larger magnitude of ground displacements and shear strains of the soil. Finally, modification factors and relative stiffness parameters are presented, indicating a greater effect of the embedment on horizontal deformations than the angular distortion of the bays

    Tunnel–framed building interaction: comparison between raft and separate footing foundations

    Get PDF
    This paper investigates the influence of the foundation configuration (raft or separate footings) on tunnel-soil-framed building interaction using geotechnical centrifuge testing. Tunnelling-induced soil movements and deformation fields, framed building displacements, and structure shear distortions (with associated modification factors) are illustrated. Framed building stiffness and footing bearing capacity are also evaluated experimentally. Results show that the foundation configuration plays an important role in determining the ground response to tunnelling, affecting soil displacement fields as well as the distribution of soil shear and volumetric strains. In particular, foundation settlements and differential horizontal displacements are larger for separate footings compared to raft foundations. The effects of building width, weight, and eccentricity (with respect to the tunnel) on foundation settlements and structural distortions is quantified for separate footings and contrasted against results for raft foundations. The modification factor of the maximum building shear distortion is linked to the relative soil-building shear stiffness; interestingly, for buildings with similar values of relative stiffness, the level of shear distortion within framed buildings is lower for separate footings than rafts

    Integrative preimplantation genetic testing analysis for a Chinese family with hereditary spherocytosis caused by a novel splicing variant of SPTB

    Get PDF
    Hereditary spherocytosis (HS), the most common inherited hemolytic anemia disorder, is characterized by osmotically fragile microspherocytic red cells with a reduced surface area on the peripheral blood smear. Pathogenic variants in five erythrocyte membrane structure-related genes ANK1 (Spherocytosis, type 1; MIM#182900), SPTB (Spherocytosis, type 2; MIM#616649), SPTA1 (Spherocytosis, type 3; MIM#270970), SLC4A1 (Spherocytosis, type 4; MIM#612653) and EPB42 (Spherocytosis, type 5; MIM#612690) have been confirmed to be related to HS. There have been many studies on the pathogenic variants and mechanisms of HS, however, studies on how to manage the transmission of HS to the next-generation have not been reported. In this study, we recruited a patient with HS. Targeted next-generation sequencing with a panel of 208 genes related to blood system diseases detected a novel heterozygous variant in the SPTB: c.300+2dup in the proband. Sanger sequencing of variant alleles and haplotype linkage analysis of single nucleotide polymorphism (SNP) based on next-generation sequencing were performed simultaneously. Five embryos were identified with one heterozygous and four not carrying the SPTB variant. Single-cell amplification and whole genome sequencing showed that three embryos had varying degrees of trisomy mosaicism. One of two normal embryos was transferred to the proband. Ultimately, a healthy boy was born, confirmed by noninvasive prenatal testing for monogenic conditions (NIPT-M) to be disease-free. This confirmed our successful application of PGT in preventing transmission of the pathogenic variant allele in the HS family

    Centrifuge application of fibre Bragg gratings: pile axial loads and wall bending moments

    Get PDF
    One challenge for geotechnical centrifuge testing of soil-structure interaction problems is the reliable measurement of induced structural strains/forces. This paper presents a novel application of fibre Bragg grating (FBG) sensors for strain measurement within geotechnical centrifuge tests. FBG sensors have several advantages for centrifuge testing, in particular their small size and minimal self-weight. This paper gives an overview of recently developed installation and calibration procedures for FBG sensors within buried centrifuge model structures. The effect of thermal expansion/contraction of the materials (including both the fibre and structures) is considered and assessed. The precision and reliability of the FBG sensors are demonstrated using verification tests. The application of the FBG sensors is considered for two geotechnical problems, namely, pile jacking and a 'retaining wall' adjacent to a tunnel (acting as a protective wall to prevent an adjacent structure from tunnelling induced ground movement). Results demonstrate that the FBG sensors can provide reliable measurements of pile axial strains/forces and protective wall bending moments. The paper provides evidence to support the routine adoption of FBG sensors for strain/force measurement of structures in geotechnical centrifuge modelling

    Increased Risk of Breast Cancer Associated with CC Genotype of Has-miR-146a Rs2910164 Polymorphism in Europeans

    Get PDF
    Background: Emerging evidence suggests that microRNAs play a critical role in the pathogenesis of breast cancer. Several molecular epidemiological studies were conducted in recent years to evaluate the association between has-miR-146a rs2910164 polymorphism and breast cancer risk in diverse populations. However, the results remain conflicting rather than conclusive. Methodology/Principal findings: We performed a meta-analysis of 6 case-control studies that included 4238 breast-cancer cases and 4469 case-free controls. We assessed the strength of the association, using odds ratios (ORs) with 95 % confidence intervals (CIs). Overall, this meta-analysis showed that the rs2910164 polymorphism was not associated with a significantly increased risk of breast cancer in all genetic models (for GC vs GG: OR = 1.00, 95 % CI = 0.9021.09, Pheterpgeneity = 0.364; for CC vs GG: OR=1.16, 95 % CI=0.9821.36, P heterpgeneity =0.757; for GC+CC vs GG: OR=1.02, 95 % CI=0.9321.12, Pheterpgeneity = 0.562; for CC vs GC+GG: OR = 1.10, 95 % CI = 0.9621.26, Pheterpgeneity = 0.441). However, in the stratified analysis by ethnicity, we found the rs2910164 polymorphism was associated with increased breast cancer risk among Europeans in homozygote comparison (CC vs. GG: OR = 1.29, 95%CI = 1.0221.63, Pheterpgeneity = 0.950, P = 0.032) and recessive model (CC vs. GC+GG: OR = 1.31, 95%CI = 1.0521.65, P heterpgeneity = 0.839, P = 0.019). No publication bias was found in the present study

    Multiancestry Genome-Wide Association Study of Lipid Levels Incorporating Gene-Alcohol Interactions

    Get PDF
    A person's lipid profile is influenced by genetic variants and alcohol consumption, but the contribution of interactions between these exposures has not been studied. We therefore incorporated gene-alcohol interactions into a multiancestry genome-wide association study of levels of high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglycerides. We included 45 studies in stage 1 (genome-wide discovery) and 66 studies in stage 2 (focused follow-up), for a total of 394,584 individuals from 5 ancestry groups. Analyses covered the period July 2014-November 2017. Genetic main effects and interaction effects were jointly assessed by means of a 2-degrees-of-freedom (df) test, and a 1-df test was used to assess the interaction effects alone. Variants at 495 loci were at least suggestively associated (P <1 x 10(-6)) with lipid levels in stage 1 and were evaluated in stage 2, followed by combined analyses of stage 1 and stage 2. In the combined analysis of stages 1 and 2, a total of 147 independent loci were associated with lipid levels at P <5 x 10(-8) using 2-df tests, of which 18 were novel. No genome-wide-significant associations were found testing the interaction effect alone. The novel loci included several genes (proprotein convertase subtilisin/kexin type 5 (PCSK5), vascular endothelial growth factor B (VEGFB), and apolipoprotein B mRNA editing enzyme, catalytic polypeptide 1 (APOBEC1) complementation factor (A1CF)) that have a putative role in lipid metabolism on the basis of existing evidence from cellular and experimental models.Peer reviewe
    corecore