Experimental Study On The Performance Of Combined Optical Fiber Sensing For Landslide Monitoring

Geologic hazard brings a lot of disasters to our nation each year. For example, it causes total economic loss to0.939billions and claim110lives just from January to June of2011. Guan Fengjun, minister of geologic environment in territorial resources department, exposes that State Council modified statement as "our nation is the heaviest one in geologic damages" from "our nation is one of the heaviest countries in geologic damages". During these geologic damages, slope collapsing is at the highest frequency, so stability supervision of slope gets more and more attention nowadays.There are varies ways of stability supervision, both merits and demerits. There are sorts of merits such as anti perilous-nature, remote control, timing dynamic, long distance and disperse supervision, high accuracy and remoteness, and however, most of all, low price.On the base of group research, this paper further researches function of this combined optical fiber sensing on the basic of research of our group. The author of this paper has designed the tiny direct shear apparatus of this equipment on his own. Besides, the author has tested a lot in condition of different cement plaster strength, different base materials of test piece. What’s more, the author also has finished the experiment through FLAC3D digital simulation and finally, come to conclusions as below:①According to ways of equipment usage, the author has designed samples to solve the problem of optical fiber clamp stability through inserting in three hard iron wires to the end of bowknot.②The intensity of stuffed mortar influences accuracy of this equipment. In a sense, the more intense the mortar is, the more accurate the equipment is.③EPS foam material equipment has wider dynamic range than plastics material equipment because different materials differ in function. While capillary steel pipe of NO.1enters foam in working progress, bowknot light loss is in proportion to load deflection which is the more light loss the lower ability for the equipment to identify displacement. Because NO.3plastic plank is in lack of displacement, NO.3capillary steel pipe is influenced so that NO.3bowknot light loss of plastic material is much smaller than foam material.④After FLAC3D digital simulation to six different optical composite fiber materials, this paper come to a conclusion:in the condition of45mm×45mm,25mm×25mm material respectively, four of them are able to judge the direction of motion well. Otherwise, equipment with mortar material has no such function.⑤In order to improve accuracy, distance, and ability of motion direction judgment, this paper suggests that researchers use45mm×45mm plastic material for composite fiber equipment to supervise slope. If possible, researchers can improve the strength of stuffed material, mortar.