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Failure process analysis of compressionshear fractured rock massbased on digital speckle technique(PDF)

长安大学学报（自然科学版）[ISSN:1006-6977/CN:61-1281/TN]

Issue:
2018年02期
Page:
34-41
Research Field:
道路工程
Publishing date:

Info

Title:
Failure process analysis of compressionshear fractured rock massbased on digital speckle technique
Author(s):
XU Wanzhong;  LIN Hang;  CAO Rihong
(1. College of Territory and Resource Engineering, Kunming University of Technology, Yunnan 650093,Kunming, China; 2. School of Resources and Safety Engineering, Central South University,Changsha 410083, Hunan, China)
Keywords:
road engineering;  fracture;  digital speckle technology;  failure mode;  strain field
PACS:
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DOI:
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Abstract:
To investigate the crack initiation, propagation and failure process of jointed rock mass under compressionshear stress environment, nonparallel fracture specimens with different dip angles were made from cement mortar materials, and the limited compression shear tests were carried out on a rigid experimental machine. At the same time, the high resolution charge coupled device (CCD) camera was used to capture images continuously. The deformation image was treated with high precision digital speckle technique, the strain field and displacement field of the surface of specimens during compression and shear loading were obtained, and then failure process between nonparallel fracture was obtained. The results show that the failure modes of nonparallel fracture specimens under the compressionshear stress can be divided into brittle failure and nonbrittle failure. For the brittle failure, there is no wing crack at the crack tip of the specimen at the initial loading stage, and the specimen is destroyed rapidly. The loading force suddenly decreases to the residual value after the peak of the loading curve. For nonbrittle failure, the loading curve of the specimen can be divided into four different stages. During the compaction stage, there is no crack in the specimen, but in the nonlinear deformation stage, the crack tip of the precast crack will be derived from the wing crack. No sudden failure occurs during the loading process, and the loading force decreases continuously after the peak of the loading curve. In addition, different fracture dip angles can lead to different failure modes. When the dip angles of fracture are 0° and 180°, there is a continuous connection between the intermittent cracks, but the main failure surface is the through shear failure surface in the middle part of the specimen. For the specimens with dip angles of 45°, 90° and 135°, no through failure surface is formed inside the specimen, the crack derived from the crack tip which extends to the boundary of the specimen causes the failure. 1 tab, 12 figs, 26 refs.

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Last Update: 2018-04-03