Results 141 to 150 of about 11,763 (288)

Study on the failure mechanism of the shield excavation face in the sandy cobble stratum under different buried depths

open access: yesDeep Underground Science and Engineering, EarlyView.
Abstract One of the significant challenges faced in shield tunnel construction is the risk of collapse resulting from abrupt changes in soil conditions in advance of the working face, particularly within the sandy cobble stratum. This study aims to effectively manage these sudden variations and to further investigate the failure mechanisms associated ...
Hua Jiang   +4 more
wiley   +1 more source

Effect of confining pressure on fracture characteristics and mineralogical behavior of tight sandstone specimens after hydraulic fracturing

open access: yesDeep Underground Science and Engineering, EarlyView.
Hydraulic fracturing in tight sandstone and fracture propagation characteristics using backscattered electron‐scanning electron microscope (BSE‐SEM) images. Abstract This study focuses on hydraulic fracturing experiments conducted under triaxial conditions on tight sandstone specimens from Shivpuri district, Madhya Pradesh, India.
Pankaj Rawat, Narendra Kumar Samadhiya
wiley   +1 more source

Performance interface document for users of Tracking and Data Relay Satellite System (TDRSS) electromechanically steered antenna systems (EMSAS) [PDF]

open access: yes
Satellites that use the NASA Tracking and Data Relay Satellite System (TDRSS) require antennas that are crucial for performing and achieving reliable TDRSS link performance at the desired data rate.
Devine, E.   +4 more
core   +1 more source

Failure characteristics and the energy criterion of rock with a through‐going joint under true‐triaxial unloading conditions: Insights from the DEM model

open access: yesDeep Underground Science and Engineering, EarlyView.
The rock failure mode is significantly influenced by the contributing factors, such as the joint inclination, the initial confining pressure, and the unloading point. We found six typical rock failure modes after a large number of numerical tests. Abstract Excavation unloading damages rock masses, with preferential failure along geological defects in ...
Fei Liu   +4 more
wiley   +1 more source

Study on fracture parameter calibration and failure characteristics of rock with hole and crack

open access: yesDeep Underground Science and Engineering, EarlyView.
The SIF and plastic zone equations for a single hole and crack have been derived. The model's failure state leads to the identification of four types of cracks. The plastic zone increases with increased brittleness and decreased crack length. Abstract Cracks within the surrounding rock of roadways significantly affect their stability and failure ...
Shaochi Peng, Wensong Wang
wiley   +1 more source

Transonic flight flutter tests of a control surface utilizing an impedance response technique [PDF]

open access: yes
Transonic flight flutter tests of the XF3H-1 Demon Airplane were conducted utilizing a frequency response technique in which the oscillating rudder provides the means of system excitation.
Mirowitz, L. I.
core   +1 more source

Review and prospects of shear test of bolted rock joints

open access: yesDeep Underground Science and Engineering, EarlyView.
The laboratory shear test equipment, test method, and numerical simulation of bolted rock joints were summarized. The shortcomings and limitations of the current research were analyzed, and the research prospects were proposed. Abstract Rock bolting is a critical approach in geotechnical engineering for supporting weak rocks.
Shulin Ren   +4 more
wiley   +1 more source

Noncontact temperature pattern measuring device [PDF]

open access: yes
This invention relates to a noncontact imagine pyrometer system for obtaining the true temperature image of a given substance in a contactless fashion without making assumptions about localized emissivity of the substance or the uniformity of the ...
Allen, J. L., Elleman, D. D., Lee, M. C.
core   +1 more source

Temperature‐dependent shear behavior and constitutive model of the rock–concrete interface

open access: yesDeep Underground Science and Engineering, EarlyView.
Shear tests were conducted to investigate the temperature‐dependent shear behavior of the rock–concrete interface, highlighting the interaction between the surrounding rock and the lining during tunnel fires. Under experimental conditions, concrete exhibited greater temperature sensitivity than rock, with the shear fracture surface transitioning from ...
Hongbin Chen   +6 more
wiley   +1 more source

The damage and failure mechanism of prestatically loaded rock during medium‐strain rate cyclic impact loading

open access: yesDeep Underground Science and Engineering, EarlyView.
Based on experimental results and theoretical analysis, an established rock damage accumulation model that comprehensively considers the preapplied static load, impact peak value, impact frequency, and impact times. Abstract To study the rock damage mechanism under high static loading and superimposed medium strain rate cyclic impact loading, a series ...
Wei Wang   +6 more
wiley   +1 more source

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