Vol9 No.1: 127-136
【Title】Laboratory Investigation of Disintegration Characteristics of Purple Mudstone under Different Hydrothermal Conditions
【Author】ZHANG Dan1,2,3, CHEN Anqiang1,2,3, LIU Gangcai1,3*
【Addresses】1 Key Laboratory. of Mountain Hazards and Earth Surface Processes, Chinese Academy of Science, Chengdu 610041, China;2 Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China;3 Graduate University of Chinese Academy of Sciences, Beijing 100049 China
【Citation】ZHANG Dan, CHEN Anqiang, LIU Gangcai. Laboratory Investigation of Disintegration Characteristics of Purple
Mudstone under Different Hydrothermal Conditions. Journal Of Mountain Science(2012) 9(1): 127–136. DOI: 10.1007/s11629-012-2204-1
【Abstract】Disintegration of rock is one of the primary processes of soil formation and geomorphology and is affected considerably by water and heat. This study focused on the disintegration characteristics under laboratory conditions of typical purple mudstone from the Tuodian group of Jurassic red beds (J3t) in Tuodian Town, Shuangbai county, Yunnan Province of southern China. The fresh mudstone was subjected to alternating applications of water, heat and hydrothermal interaction during five treatments: wetting-drying (WD), saturation (ST), refrigeration-heating (RH), a combination of wetting-drying and refrigeration-heating (WDRH), and a combination of saturation and refrigeration-heating (STRH). Each treatment was run in twenty-four cycles. The results showed that there are three types of disintegration: collapsing disintegration, exfoliation disintegration and imperceptible disintegration. The cumulative disintegration rate (percentage of cumulative disintegrated mass to the initiative sample mass passed through a 2 mm sieve) produced a ‘S’-shape function when related to treatment cycle time and closely fit a logistic model (R2 > 0.99). The rank order of the cumulative disintegration rate resulting from the five treatments was as the following: WDRH > STRH > ST > WD > RH. Because of alternating periods of moisture and dryness, WD caused the most disintegration, while RH alone resulted in imperceptible disintegration. Additionally, there was a negative correlation between the disintegration rate of each treatment cycle (percentage of disintegrated mass to the treated sample mass) and treatment cycle number. There was a positive correlation between this rate and temperature change under moist conditions, indicating that a change in temperature greatly accelerates the disintegration of parent rock when water was supplied.
【Keywords】Physical weathering; Mudstone; Rock disintegration; Hydrothermal interaction; Water alternation; Heat alternation