Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: odkształcenia ścinania

Sortuj według:

Ogranicz wyniki do:

New constitutive model based on disturbed state concept for shear deformation of rock joints

Xie Shijie, Lin Hang, Chen Yifan

Archives of Civil and Mechanical Engineering

2023

Vol. 23, no. 1

art. no. e26, 2023

The mechanical behavior and constitutive relation of rock joints have caught more and more attention in the field of geotechnical engineering. The disturbed state concept (DSC) theory offers a powerful tool for building a constitutive model to interpret the mechanical response of geomaterials. In this paper, a new constitutive model for joint shear deformation was developed based on the DSC theory. The characteristics of quasi-elastic phase, pre-peak hardening phase, peak shear strength, post-peak softening phase and residual strength during the whole process of joint shear deformation are considered in this model. In the framework of this shear constitutive model, the rock material was assumed to consist of two kinds of micro-units with different mechanical responses, namely the relatively intact unit and the fully adjusted unit. Subsequently, the DSC theory was used to connect the mechanical behavior of micro-units with the macroscopic joint shear deformation characteristics, and a disturbance factor was introduced to reveal the disturbed state evolution process inside the rock. In addition, the proposed DSC model was simple in form, less in parameters and reasonable in physical meaning. The model was cross-validated by experimental data of different kinds of natural joints and artificial joint replicas. Finally, the model is compared with existing models, and the model effectiveness is quantitatively evaluated through statistical indicators. The values of R2 are greater than 0.9, and the AAREP and RMSE of the proposed DSC model are closer to 0 than those of other models. The research results can provide a valuable reference for further understanding of shear deformation mechanism.

Projektowanie mostów stalowych : komentarz do prENV 1993-2: 1997

Czudek H.

Prace Instytutu Badawczego Dróg i Mostów

1998

nr 1-2

43-80

Komentarz do Eurokodu prENV 1993-2: 1997 "Projektowanie mostów stalowych" składa się z dwóch części. W pierwszej części przedstawiono te zagadnienia projektowe związane ze stanami granicznymi użytkowania i nośności, które wymagają korzystania z innych Eurokodów lub norm europejskich. Zagadnienia te dotyczą przede wszystkim wyboczenia, także wyboczenia giętno-skrętnego, zmęczenia, odkształcenia ścinania (tzn. shear lag), miarodajnej długości efektywnej przy obliczaniu wytrzymałości elementu, obliczania łączników. W drugiej części przedstawiono teorię wyboczenia cienkich blach, opartą na liniowej teorii wyboczenia cienkich płyt oraz na zachowaniu się płyt w obszarze nadkrytycznym (wg von Karmana). Na zakończenie podano przykład obliczenia smukłości granicznych dwuteownika poddanego czystemu zginaniu.

This elaboration presents principles and rules defined in prENV 1994-2: 1997 which should be applied in design of composite bridge structures. Basis of this design, material characteristic, strength criteria as well as serviceability and ultimate limit states were described. More exactly were described these pronciples which at presently used design methods have not been (or have been rather rerely) taken into account. It concerns particularly: the conjunction with use of studs, the fatigue strength, the limit states and the use of prestress.