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In this study, we propose a method for predicting the supporting pressure required for shallow tunnels in layered soils, based on a curved roof collapse mechanism with multi-failure surfaces. In this method, the effect of the number and thickness of soil layers, pore water pressure, arbitrary roof profile, and ground additional load is considered simultaneously. A nonlinear power-law failure criterion is employed to describe the failure characteristics of the roof soils. The internal energy dissipation rate and the work rates produced by external forces are obtained based on the associated flow rule and plasticity potential theory. The analytical expressions of the required supporting pressure and roof collapse surfaces are obtained with the upper bound method. Furtherly, a shallow rectangular tunnel in two soil layers is selected for parametric investigation. The change laws of the required supporting pressure and collapse curves under varying parameters are obtained. Furthermore, the corresponding engineering recommendations are given, which may potentially provide references for the support design and construction of shallow tunnels in layered strata.
This article was published in the following journal.
Name: PloS one
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Shallow foundation is a common foundation type that is usually used for small to medium size structures. The bearing ability and the failure mechanism of shallow foundation are the fundamental concern...
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We use the transparency of zebrafish embryos to reveal the generation of a simple squamous epithelium and identify the cellular architecture in the epithelial transition zone that ties this squamous ...
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To compare the rapid shallow breathing index (RSBI) values, the incidence of adverse reactions, and the predictive accuracy measured under 5 different ventilator strategies in the same pat...
Through this study the investigators aim to clarify the relationship between trans-diaphragmatic pressure and various parameters of the diaphragmatic contraction evaluated by ultrasound. T...
ACL reconstruction in the Division of Orthopaedic surgery at Queen's is currently being performed arthroscopically assisted. The resultant function of the reconstructed ligament is greatly...
Phacoemulsification in eyes with a shallow anterior chamber (ACD < 2.2mm) presents with problems of safe access to the cataract and increased vulnerability of the endothelium and a higher ...
We will compare two groups for acute patella tendon repair: one treated with surgical anchors and the second, with transpatellar tunnels.
Double-layered inflatable suits which, when inflated, exert pressure on the lower part of the wearer's body. The suits are used to improve or stabilize the circulatory state, i.e., to prevent hypotension, control hemorrhage, and regulate blood pressure. The suits are also used by pilots under positive acceleration.
The pressure within the CARDIAC ATRIUM. It can be measured directly by using a pressure catheter (see HEART CATHETERIZATION). It can be also estimated using various imaging techniques or other pressure readings such as PULMONARY CAPILLARY WEDGE PRESSURE (an estimate of left atrial pressure) and CENTRAL VENOUS PRESSURE (an estimate of right atrial pressure).
Predicting the time of OVULATION can be achieved by measuring the preovulatory elevation of ESTRADIOL; LUTEINIZING HORMONE or other hormones in BLOOD or URINE. Accuracy of ovulation prediction depends on the completeness of the hormone profiles, and the ability to determine the preovulatory LH peak.
The blood pressure in the VEINS. It is usually measured to assess the filling PRESSURE to the HEART VENTRICLE.
Persistently high systemic arterial BLOOD PRESSURE. Based on multiple readings (BLOOD PRESSURE DETERMINATION), hypertension is currently defined as when SYSTOLIC PRESSURE is consistently greater than 140 mm Hg or when DIASTOLIC PRESSURE is consistently 90 mm Hg or more.