Research on grounding environment of high altitude buildings in Tibet
Sun Jianh · Sichuan Building Science · 2013
Lightning disaster of buildings is serious in the high altitude area of Tibet. In order to clarify its grounding environment and explore suitable lightning protection and grounding resistance reduction measures,rock samples were taken from the construction site and cylindrical rock samples were taken by rock drilling machine. Then metal electrodes were bonded to the samples' ends surface with conductive glue. Resistivity of rock under different ambient temperature was tested in the DC voltammetry resistance test system using two-pole method. The results showed that: resistivity of granite is great than that of sandstone due to the influence of composition minerals. Rock resistivity will increase with temperature decreasing and influence of positive temperature on rock resistivity is slight while that of negative temperature on rock resistivity is critical. Granite resistivity under-30℃ is 11 times larger than that under 10℃. In general,for the granite rock types,lightning strikes occur in the winter and mainly in the night,grounding environment of the high altitude buildings is very poor.