WANG Zhiming, LIU Cong, XU Tiancheng, REN Dong, SHANG Jingnan, ZHANG Bo, PEI Qiangqiang, WU Jian, GUO Qinglin
2023, 2(2):
78-87.
In order to measure data on the compression strain sustained by adobe masonry placed on a raw soil foundation,researchers formed adobe mud into 7×14×30 cm3 bricks using a dry beating process. Through uniaxial compression tests,which were conducted with flat compression on a 14×30 cm2 area,the study obtained a strain deterioration curve along X and Y axes for digital speckle data displacement. Additionally,a traditional strain gauge measurement was also used to measure the strain along the same set of axes while using a curved surface for compression. Non-destructive tests under similar conditions show that the micro strains in both X and Y directions obtained by using digital speckle techniques exhibit fluctuating positive and negative numerical values. This indicates that the reliability of digital speckle technology for non-destructive testing of adobe materials(under small pressure ranges) is not particularly high,a fact that is likely due to measurement errors caused by microscopic discontinuous gaps caused by the internal compression of soil particles inside the adobe. Attaching a strip strain gauge to the adobe and then using traditional strain gauge technology in order to obtain the statistical strain average,however,has proven to provide relatively accurate and reliable results. The results obtained by using digital speckle technology in destructive tests were found to be basically consistent with those obtained by using traditional stress gauge measurement techniques,which can be reasonably explained by the angle at which the two measurement techniques reached the threshold of displacement,leading to sudden changes in various dependent variables as detected by the test equipment when data fluctuations approached a peak. The data curve of the strain relationship for dry adobe under compression provides references for the application of adobe masonry in real-world projects and site repair, and can also be used as supporting data for relevant codes and standards of earthen site maintenance.