نتایج جستجو برای: hard rock pillar design

تعداد نتایج: 1132503  

Journal: :ACS applied materials & interfaces 2015
Navid Sakhavand Rouzbeh Shahsavari

Although boron nitride nanotubes (BNNT) and hexagonal-BN (hBN) are superb one-dimensional (1D) and 2D thermal conductors respectively, bringing this quality into 3D remains elusive. Here, we focus on pillared boron nitride (PBN) as a class of 3D BN allotropes and demonstrate how the junctions, pillar length and pillar distance control phonon scattering in PBN and impart tailorable thermal condu...

2017
Yang Yu Shen-en Chen Ka-zhong Deng Hong-dong Fan

The collapse of abandoned room-and-pillar mines is often violent and unpredictable. Safety concerns often resulted in mine closures with no post-mining stability evaluations. As a result, large amounts of land resources over room-and-pillar mines are wasted. This paper attempts to establish an understanding of the long-term stability issues of goafs (abandoned mines). Considering progressive pi...

Journal: :Advances in Civil Engineering 2023

Tensile strength is an important control parameter for the design and stability analysis in rock engineering. In order to reveal influence of elastic modulus on tensile test results, Brazilian splitting tests were carried out specimens with different strengths, such as mudstone, white sandstone, green red marble. Longitudinal transverse strains monitored analyze maximum contact angle peak load ...

1999

The drill & blast method is still the most typical method for medium to hard rock conditions. It can be applied to a wide range of rock conditions. Some of its features include versatile equipment, fast start-up and relatively low capital cost tied to the equipment. On the other hand, the cyclic nature of the drill & blast method requires good work site organization. Blast vibrations and noise ...

2006
Thomas J. Ahrens

A new instrument for measuring the in siru level of stress in boreholes has been developed. The instrument operates on the principle of locally relieving the stresses acting on a rock mass by drilling a small hole into the borehole surface and recording the resultant displacement field by holographic interferometry. Because the recording technique is optical, the entire displacement field due t...

2014
Susmitha valli Gogula CH Divakar CH Satyanarayana Allam Appa Rao

The paper presents a new approach for medical image segmentation. Exudates are a visible sign of diabetic retinopathy that is the major reason of vision loss in patients with diabetes. If the exudates extend into the macular area, blindness may occur. Automated detection of exudates will assist ophthalmologists in early diagnosis. This segmentation process includes a new mechanism for clusterin...

Journal: :Advances in Civil Engineering 2022

When shield machine traverses through hard rock mass, disc cutters will be abraded to different degrees. Excessive height difference exists between adjacent cutters, which critically affects the rock-breaking efficiency. Relying on a section of mass in Qingdao, cutter abrasions are measured site, and reason for low construction efficiency is analysed. Subsequently, discrete element method used ...

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