Research On The Indoor Static Water Settlement Of Yunnan Laterite Sediment

Laterite has regional particularity,which is different from other soils.The clay type sediment belongs to the viscous fine particle sediment,the viscous sediment in the sedimentation process is affected by many factors such as the external environment,inorganic ions,the sedimentation process has the complexity.Therefore,the study of sedimentation of laterite type sediment under different conditions is of great significance to the in-depth understanding of the sedimentation law of cohesive sediment in different regions and different lands.And for the river and reservoir dredging also has certain significance.Taking yunnan laterite sediment as the research object,this paper adopts the methods of indoor hydrostatic sedimentation,pipette method and theoretical analysis.The sedimentation characteristics of laterite type were studied by setting different particle sizes,salinity,sediment content,temperature and cations.On the basis of comprehensive test and theoretical analysis,the sedimentation rule of laterite type sediment under different conditions is clarified,which can provide reference for the prevention and treatment of silting in rivers and reservoirs in yunnan.When the test water is tap water,the sedimentation law of the laterite type sediment under different conditions: the sedimentation speed increases gradually with the increase of sediment particle size.By comparing the calculated value with the experimental value,it can be known that the sedimentation velocity is not different.At the same time,temperature will also affect the sedimentation rate.The sedimentation velocity increases with the increase of temperature,and the relationship between temperature and sedimentation velocity of laterite type sediment is a function with good correlation coefficient.But the effect of temperature decreases when the sediment content is large.With the increase of sediment content,the sedimentation velocity increases first and then decreases.When the sediment content is between0.5-3 kg/m3,the sedimentation is accelerated,and the sedimentation velocity is notvery different under different salt content.When the sediment content is between 3-8kg/m3,the sedimentation velocity is stable.When the sediment content is greater than8 kg/m3,the sediment deposition is in the deceleration stage.The relationship between the sediment content and the sedimentation of laterite type is exponential.When the salinity is different and the sedimentation velocity of the sediment is different at different sediment contents,the sedimentation velocity in the experiment in this paper is between 0.1-0.5cm/s.The sedimentation rate increases with the increase of salt content,but the effect of salt content on sediment sedimentation is small when the sediment content is large.Under different sediment contents,the best sedimentation salinity is different at the fastest sedimentation speed.When the sediment content is within the range of 0.5-1.6kg/m3,the best sedimentation salinity of the laterite type sediment is about 12‰.When the sediment content is between2-7kg/m3,the optimal salt content is 15‰.The relation between salinity and sedimentation velocity of laterite type sediment is quadratic function on the whole.When the test water is distilled water.1)when the salt content is 0-0.9‰ and the concentration of Al3+ and Fe3+ is within the range of 0-0.9mmol/L,the relative concentration of sediment at the same depth of the liquid surface decreases exponentially with time.2)when the concentration of Al3+ is within the range of0-0.5mmol/L,the sedimentation rate gradually accelerates with the increase of the concentration.When the Fe3+ concentration is within the range of 0-0.9mmol/L,the sedimentation rate gradually slows down with the increase of the concentration.3)the relationship between salinity and Al3+ concentration and the sedimentation velocity of the laterite type sediment was quadratic function,while the relationship between Fe3+ concentration and the sedimentation velocity of the laterite type sediment was exponential.The general formula of Al3+ and Fe3+ to calculate the sedimentation velocity of laterite type is obtained by sorting out the experimental data and theoretical analysis.The sedimentation velocity of sediment is closely related to the environment,inorganic cation species and concentration.