Study On Flow And Mechanical Properties Of Solidified Waste Mud With High Water Content Considering Fiber Reinforcement Effect

In recent years,large-scale dredging work has been carried out in my country’s ports and wharves,resulting in a large amount of dredged silt.Due to the high water content,high compressibility,and extremely low strength of dredged silt,cofferdams are often used in construction sites to deal with dredged silt,but its consolidation time is long and the bearing capacity is low.On the one hand,it will occupy the land for a long time and cannot be timely.Returning farmland back to farmers leads to waste of land resources;it cannot be used directly as building materials.On the other hand,due to the abundant straw resources,the current straw returning to the field can effectively improve the soil properties and produce nutrient elements required by plants.Therefore,this paper proposes to use straw to improve the physical properties,planting performance and natural dehydration performance of the dredged sludge,and analyze the fluidity,viscosity,plasticity index,particle size,specific gravity,PH,loss on ignition,and nutrition of the dredged sludge.The main research results of the influence laws of elements(C,N,P,K)are as follows:(1)The higher the moisture content of dredged sludge,the greater its fluidity.The fluidity of dredged sludge with a moisture content of 106%is 0.5 times lower than that of dredged sludge with a moisture content of 133%;the fluidity decreases with the increase in the amount of straw and the degradation time of straw.When it is degraded to 90 days,the fluidity of dredged sludge can be reduced by about 16cm;the viscosity coefficient and dynamic shear force of dredged sludge increase nonlinearly with the increase of straw content and straw degradation time.(2)The liquid limit and plastic limit of dredged sludge increase within 14 days of straw degradation,and the highest can reach 72%and 43%,respectively,and decrease slightly within 14 to 90 days.The plasticity index is the same as the liquid limit and plastic limit;when the straw is degraded to 14 days,the plasticity index can increase to 36.The specific gravity of dredged silt decreased sharply from 2.648 to 2.5 within 0-14 days of straw degradation,and stabilized within 14-90 days;its clay content would increase with the increase of straw degradation time;the powder content would decrease.(3)The lower the water content of the dredged silt,the higher the amount of straw,and the more nutrient elements produced by the degradation of straw.Among them,the content of C and N can be increased by 10g/kg,0.1g/kg than the original sludge,and the C/N ratio can be as high as 13.5;the content of P and K can be increased by 10mg/g,11mg/g than the original sludge.The loss on ignition gradually increased with the degradation of straw;the PH value decreased slightly with the degradation of straw.(4)Straw can effectively accelerate the natural dehydration and consolidation of dredged sludge,and can also change the destruction mode of dredged sludge;the amount of straw is 3%and the size of straw is 0.6～1mm for the best dehydration effect of dredged sludge;With the increase in volume and size,the number of main cracks will decrease and the number of secondary cracks will increase;secondary cracks mainly develop vertically.Figure 45 Table 4 Reference 85...