Subjects: Geosciences >> Geology submitted time 2020-03-26
Abstract: "
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Geology submitted time 2020-03-26
Abstract: " "
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Geochemistry submitted time 2020-03-26
Abstract: Water-rock (soil) chemical interaction (CWRI) is of special significance in the formation process of rainfall induced landslide. On the one hand, rain erosion will cause damage to rock and soil mass, on the other hand, it will generate a large number of secondary clay minerals. The main reason for the formation of the sliding surface is the decrease of the shear strength of the sliding surface caused by the corrosion damage and the enrichment of secondary clay minerals in the sliding surface. In this paper, a high pressure open flow system is used to simulate the chemo-mechanical environment of the sliding surface. Taking calcite and montmorillonite as examples, the rate and controlling factors of the dissolution reaction of the minerals on the sliding surface are studied, so as to reveal the formation mechanism of the sliding surface and its chemo-mechanical process. The results show that: 1) the dissolution rate of minerals increases with the increase of pressure, but the response of different minerals to pressure is different; 2) with the decrease of pH value of solution, the H + activity increases gradually, and the dissolution rate of minerals increases significantly; 3) the flow rate effect of mineral dissolution is very complex, which is related to pressure, pH and mineral species; 4) the dissolution of minerals does not meet the stoichiometric relationship. The above experimental results show that the dissolution on the sliding surface is closely related to the damage of soil and the evolution of the strength of the sliding surface. The depth of the sliding surface, the types of minerals and the acidity and alkalinity of groundwater jointly determine the dissolution rate and transformation characteristics of the minerals on the sliding surface. The increase of the depth of the sliding surface or the increase of the soluble minerals accelerates the formation of the sliding surface. The increase of the acidity of groundwater will accelerate the water rock reaction rate, and thus accelerate the decrease of the strength of the sliding surface.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Other Disciplines of Geosciences submitted time 2019-09-09 Cooperative journals: 《干旱区研究》
Abstract:干旱是柯西河流域中山区发生最为频繁的气象灾害之一,对农业生产造成极大的影响。利用气象、农业数据,结合线性趋势、回归分析等方法,分析了1998—2015年研究区的干旱变化特征及其对作物单产增长率的影响。结果表明:① 研究区作物缺水指数呈先上升后下降的趋势,就作物缺水程度来看,南部干旱灾害最为严重,中部其次,北部最轻;② 干旱对不同作物产量的影响差异显著。当0.60≤CWSI(作物缺水指数)<0.63时,小麦单产增长率受到干旱的影响;当0.63≤CWSI<0.64时,马铃薯和小麦受到干旱影响;当0.64≤CWSI<0.65时,大麦、马铃薯和小麦受到干旱影响;当0.65≤CWSI<0.66时,玉米、大麦、马铃薯和小麦受到干旱影响;当CWSI≥0.66时,玉米、大麦、马铃薯、小麦和水稻等5种作物均受到干旱影响;③ 干旱对作物产量的影响存在显著的区域差异,不同地区的作物受干旱影响的临界值和程度不同。