The nature of the slurry from the stone-crushing and sand-making processes is analyzed to develop a novel separation process.The process comprises hydro-cyclone separation followed by screening of the fines,clarificat...The nature of the slurry from the stone-crushing and sand-making processes is analyzed to develop a novel separation process.The process comprises hydro-cyclone separation followed by screening of the fines,clarification,and filtration.Recovering fine sand and clean wastewater for recycle is demonstrated.The +0.045 mm fine sand fraction and à0.045 mm ultra-fine clay in the slurry are separated and recovered.Fine sand that was previously lost and wasted is now recoverable.The cleaned and reused water is as much as 94% of the total.展开更多
The lithology of fracture zone which was developed at the dam foundation of a hydropower station is weak sandstone with poor integrity and pore cementation contact.Its creep properties have a significant impact on the...The lithology of fracture zone which was developed at the dam foundation of a hydropower station is weak sandstone with poor integrity and pore cementation contact.Its creep properties have a significant impact on the deformation and stability of the dam.Based on the characteristics of loose organizational structure,high moisture content and poor mechanical properties,the triaxial compression tests and creep tests were carried out,respectively.The results show significant non-linear,low strength and no obvious strength peaks.Both axial and lateral strains are achieved more than 3%when the tests are failed.The weak sandstone has a significant creep property,but only transient and steady state appear under low stress.Increased stress causes creep intensified and lateral strain gradually exceeds axial strain.In the failure stage,it has characteristics of large axial plastic deformation,obvious volumetric ductility dilation and large steady creep rate.The accelerated creep appears shortly after transient loading under confining of pressures 1.0 MPa and 1.5 MPa.Therefore,an improved Burgers creep model considering the non-linear characteristics of weak sandstone is built based on hyperbolic equation and the creep parameters are identified.This model can well describe the creep properties of weak sandstone.展开更多
This paper presents particle breakage and the mobilized drained shear strengths of sand with the purpose of clarifying the influence of particle breakage on the mobilized shear strengths of sand. Several drained triax...This paper presents particle breakage and the mobilized drained shear strengths of sand with the purpose of clarifying the influence of particle breakage on the mobilized shear strengths of sand. Several drained triaxial tests were carried out on Silica sand No.5 under 3 MPa confining pressure to produce the pre-crushed sands in simulating the high- pressure shear process on soil to result in particle breakage, and then the pre-crushed sands were re- sheared in series of drained triaxial tests to investigate the mobilized strengths of the pre-crushed sands in detecting the influence of particle breakage. It was found that, by deteriorating strain-stress behavior, particle breakage resulted in change of stress-dilataney behavior in translation and rotation of the relation of the dilatancy factor and the effective principal stress ratio. For a given initial void ratio, particle breakage resulted in impairment of dilatancy behavior of soil to be more contractive in deterioration of the mobilized friction angle and the mobilized dilatancy angle and reduction of void ratio. However, particle breakage resulted in increase of the mobilized basic friction angle especially before failure. In addition, the influence of particle breakage on the mobilized strengths was revealed to be influenced by the shear stress-strain state.展开更多
基金financially supported by Xinkaiyuan Crushed Stones Co. Ltd
文摘The nature of the slurry from the stone-crushing and sand-making processes is analyzed to develop a novel separation process.The process comprises hydro-cyclone separation followed by screening of the fines,clarification,and filtration.Recovering fine sand and clean wastewater for recycle is demonstrated.The +0.045 mm fine sand fraction and à0.045 mm ultra-fine clay in the slurry are separated and recovered.Fine sand that was previously lost and wasted is now recoverable.The cleaned and reused water is as much as 94% of the total.
基金Project(2011CB013504)supported by the National Basic Research Program of ChinaProject(11172090)supported by the National Natural Science Foundation of China
文摘The lithology of fracture zone which was developed at the dam foundation of a hydropower station is weak sandstone with poor integrity and pore cementation contact.Its creep properties have a significant impact on the deformation and stability of the dam.Based on the characteristics of loose organizational structure,high moisture content and poor mechanical properties,the triaxial compression tests and creep tests were carried out,respectively.The results show significant non-linear,low strength and no obvious strength peaks.Both axial and lateral strains are achieved more than 3%when the tests are failed.The weak sandstone has a significant creep property,but only transient and steady state appear under low stress.Increased stress causes creep intensified and lateral strain gradually exceeds axial strain.In the failure stage,it has characteristics of large axial plastic deformation,obvious volumetric ductility dilation and large steady creep rate.The accelerated creep appears shortly after transient loading under confining of pressures 1.0 MPa and 1.5 MPa.Therefore,an improved Burgers creep model considering the non-linear characteristics of weak sandstone is built based on hyperbolic equation and the creep parameters are identified.This model can well describe the creep properties of weak sandstone.
基金The financial assistance by China Scholarship Council (Grant No. 2011671035)the National Basic Research Program of China (973 Program) (Grant No. 2013CB733201)+3 种基金Key Program of Chinese Academy of Sciences (Grant No. KZZDEW-05-01)One-Hundred Talents Program of Chinese Academy of Sciences (SU Li-jun)CAS "Light of West China" Program (Grant No. Y6R2250250)Youth Fund of Institute of Mountain Hazards and Environment, Chinese Academy of Sciences (Grant No. Y6K2110110)
文摘This paper presents particle breakage and the mobilized drained shear strengths of sand with the purpose of clarifying the influence of particle breakage on the mobilized shear strengths of sand. Several drained triaxial tests were carried out on Silica sand No.5 under 3 MPa confining pressure to produce the pre-crushed sands in simulating the high- pressure shear process on soil to result in particle breakage, and then the pre-crushed sands were re- sheared in series of drained triaxial tests to investigate the mobilized strengths of the pre-crushed sands in detecting the influence of particle breakage. It was found that, by deteriorating strain-stress behavior, particle breakage resulted in change of stress-dilataney behavior in translation and rotation of the relation of the dilatancy factor and the effective principal stress ratio. For a given initial void ratio, particle breakage resulted in impairment of dilatancy behavior of soil to be more contractive in deterioration of the mobilized friction angle and the mobilized dilatancy angle and reduction of void ratio. However, particle breakage resulted in increase of the mobilized basic friction angle especially before failure. In addition, the influence of particle breakage on the mobilized strengths was revealed to be influenced by the shear stress-strain state.
