In this paper, through the indoor free load swelling rate test, expansive soil in a section of a first- class highway reconstruction project in Yichang City was studied. It emphatically analyzed the interrelations amo...In this paper, through the indoor free load swelling rate test, expansive soil in a section of a first- class highway reconstruction project in Yichang City was studied. It emphatically analyzed the interrelations among free load swelling rate, non-load time, the proportion of mixed sand and initial dry density. Experimen- tal studies have shown that： Free load swelling deformation is mainly divided into three stages of rapid expan- sion, slow expansion and final stability; when the initial dry density is constant, free load swelling rate of the weathered sand modified soil will reduce rapidly before they slow down with the increase of sand proportion, and weathered sand modified soil free load swelling rate is not sensitive to the large amount of sand mixed; in the same mixed sand ratio, weathered sand modified soil free load swelling rate increases rapidly with the in- crease of initial dry density, there is a good linear correlation between them. To take appropriate control of the initial dry density during the expansive soil subgrade construction helps to reduce its swelling deformation and ensures the stability of the embankment.展开更多
This paper proposes a scheme for detecting the swell decay of a moving typhoon. We considered a typhoon that was neither far from a point source nor had a belt-like homogenous source,as previously studied. We tracked ...This paper proposes a scheme for detecting the swell decay of a moving typhoon. We considered a typhoon that was neither far from a point source nor had a belt-like homogenous source,as previously studied. We tracked the swell close to the source during a typhoon in the western North Pacific Ocean. We used wind speed and significant wave height data derived from the Geophysical Data Record of the Jason-1 altimeter and the best-track information of the typhoon from the China Meteorological Administration tropical cyclone database. We selected three specific cases to reveal the decay characteristics of the swell generated by a moving typhoon. Based on an altimeter-based typhoon swell identification scheme and the dispersion relationship for deep water,we relocated the swell source for each altimeter measurement. The subsequent statistical decay coefficient was comparable to previous studies,and effectively depicted the swell propagation conditions induced by the typhoon. We hope that our results provide a new understanding of the characteristics and wave energy budget of the North Pacific Ocean,and significantly contribute to wave modeling in this region.展开更多
Black shale is widely distributed in southern and western China.The swelling and breakdown characteristics of black shale are important physicomechanical properties in engineering activities.Aqueous solutions with dif...Black shale is widely distributed in southern and western China.The swelling and breakdown characteristics of black shale are important physicomechanical properties in engineering activities.Aqueous solutions with different compositions exert various influences on the swelling characteristic of black shale because of the complexity of its composition.Soils derived from black shale are most commonly developed on black shales with bedded horizons that generally have cutting and weathering profiles.This paper reports an axial free swelling study for soils derived from black shales and developed in the Lower Cambrian black shales in Chengkou County,Chongqing Municipality,Southwest China.To discuss the swelling characteristics of black shale under the influence of cations,an axial free swelling test was conducted on black shale samples while considering the initial water content,weathering stage of black shale,and different cationic solutions with various concentrations.Results showed that the swelling deformation curve of black shale could be divided into three phases:acceleration,deceleration,and stability.The axial swelling ratio eventually decreased with increasing water content,and the axial free swelling rate changed with the free expansion model of the exponential relationship.Under a constant initial water content,the axial swelling rate increased with the intensity of black shale weathering in the same immersion solution.When different types of immersion solutions were used,the cationic price was high and the axial swelling rate increased with rising cation valence.The changes in the swelling ratio were significant at a valence of one or two.The results of this study provide further understanding of the engineering geological characteristics of black shale and the geological hazards caused by the swelling characteristics of black shale.展开更多
Swell and sag drawdown significantly influence the high density polyethylene parison. Nu- merical simulations of the flow field of a HDPE melt were performed using the finite element method for the die of plastic pipe...Swell and sag drawdown significantly influence the high density polyethylene parison. Nu- merical simulations of the flow field of a HDPE melt were performed using the finite element method for the die of plastic pipe extrusion and parison formation. The constitutive equation of Carreau law was used to describe the polymer melt in the flow domain. The distributions of the velocity, shear rate, viscosity, pressure, thickness and radius are presented with Polyflow. The effect of flow rate and temperature on extrusion swell and parison sag was investigated. The results show that the thickness of the parison increases with increasing flow rate. The thickness and radius of the parison are more sensitive to changes in flow rates than to changes in temperatures.展开更多
以羧甲基纤维素(CMC)、聚乙烯醇(PVA)、β-环糊精(β-CD)为原料,在碱性条件下与环氧氯丙烷(ECH)发生交联反应,制备具有高溶胀性能的CMC-PVA-β-CD三元复合水凝胶,并研究了CMC,PVA,ECH,β-CD添加量对水凝胶溶胀性能、力学性能的影响。结...以羧甲基纤维素(CMC)、聚乙烯醇(PVA)、β-环糊精(β-CD)为原料,在碱性条件下与环氧氯丙烷(ECH)发生交联反应,制备具有高溶胀性能的CMC-PVA-β-CD三元复合水凝胶,并研究了CMC,PVA,ECH,β-CD添加量对水凝胶溶胀性能、力学性能的影响。结果表明:加入20.0 mL水,0.52 g CMC,0.20 g PVA,1.2 mL ECH,0.24 gβ-CD时,水凝胶溶胀率最高,为2 040.62 g/g,压缩应力为7.90 kPa。与PVA-CMC二元水凝胶相比,CMC-PVA-β-CD三元水凝胶的压缩应力和结晶度均有提高。该三元复合水凝胶具有较高的溶胀率和良好的力学性能,在生物医药、消毒杀菌领域具有很高的应用价值。展开更多
Deep and ultra-deep reservoirs have dense matrix and high fracture pressure, which leads to high pressure and difficulty in fracturing construction. Conventional aggravated fracturing fluids have the problems of low a...Deep and ultra-deep reservoirs have dense matrix and high fracture pressure, which leads to high pressure and difficulty in fracturing construction. Conventional aggravated fracturing fluids have the problems of low aggravation efficiency, high friction resistance, etc., and the reduction of construction pressure cannot reach the theoretical effect. In view of the above problems, this paper adopts the weighting agent HD160 and the drag reducing agent JHFR-2 to form a new type of weighted slippery water fracturing fluid system. And the weighting performance, drag reduction performance, corrosion performance, anti-expansion performance and reservoir damage of this system were studied. The results show that the density of the system is adjustable within 1.1 - 1.6 g·cm−3, and the drag reduction rate can be up to 68% at 1.5 g·cm−3, with low corrosion rate, surface tension less than 28 mN·m−1, anti-expansion rate as high as 94.5%, and the damage rate of the reservoir permeability is less than 10%, which is of good application prospect.展开更多
文摘In this paper, through the indoor free load swelling rate test, expansive soil in a section of a first- class highway reconstruction project in Yichang City was studied. It emphatically analyzed the interrelations among free load swelling rate, non-load time, the proportion of mixed sand and initial dry density. Experimen- tal studies have shown that： Free load swelling deformation is mainly divided into three stages of rapid expan- sion, slow expansion and final stability; when the initial dry density is constant, free load swelling rate of the weathered sand modified soil will reduce rapidly before they slow down with the increase of sand proportion, and weathered sand modified soil free load swelling rate is not sensitive to the large amount of sand mixed; in the same mixed sand ratio, weathered sand modified soil free load swelling rate increases rapidly with the in- crease of initial dry density, there is a good linear correlation between them. To take appropriate control of the initial dry density during the expansive soil subgrade construction helps to reduce its swelling deformation and ensures the stability of the embankment.
基金Supported by the National Natural Science Foundation of China(Nos.41331172,61361136001,U1406404)the National High Technology Research and Development Program of China(863 Program)(No.2013AA09A505)
文摘This paper proposes a scheme for detecting the swell decay of a moving typhoon. We considered a typhoon that was neither far from a point source nor had a belt-like homogenous source,as previously studied. We tracked the swell close to the source during a typhoon in the western North Pacific Ocean. We used wind speed and significant wave height data derived from the Geophysical Data Record of the Jason-1 altimeter and the best-track information of the typhoon from the China Meteorological Administration tropical cyclone database. We selected three specific cases to reveal the decay characteristics of the swell generated by a moving typhoon. Based on an altimeter-based typhoon swell identification scheme and the dispersion relationship for deep water,we relocated the swell source for each altimeter measurement. The subsequent statistical decay coefficient was comparable to previous studies,and effectively depicted the swell propagation conditions induced by the typhoon. We hope that our results provide a new understanding of the characteristics and wave energy budget of the North Pacific Ocean,and significantly contribute to wave modeling in this region.
基金sponsored by the Natural Science Foundation of China (Grant Nos.41172261 and 41472256)supported by the Scientific Research Fund of Sichuan Provincial Education Department (Grant Nos.13ZA0173 and 15ZA0121)
文摘Black shale is widely distributed in southern and western China.The swelling and breakdown characteristics of black shale are important physicomechanical properties in engineering activities.Aqueous solutions with different compositions exert various influences on the swelling characteristic of black shale because of the complexity of its composition.Soils derived from black shale are most commonly developed on black shales with bedded horizons that generally have cutting and weathering profiles.This paper reports an axial free swelling study for soils derived from black shales and developed in the Lower Cambrian black shales in Chengkou County,Chongqing Municipality,Southwest China.To discuss the swelling characteristics of black shale under the influence of cations,an axial free swelling test was conducted on black shale samples while considering the initial water content,weathering stage of black shale,and different cationic solutions with various concentrations.Results showed that the swelling deformation curve of black shale could be divided into three phases:acceleration,deceleration,and stability.The axial swelling ratio eventually decreased with increasing water content,and the axial free swelling rate changed with the free expansion model of the exponential relationship.Under a constant initial water content,the axial swelling rate increased with the intensity of black shale weathering in the same immersion solution.When different types of immersion solutions were used,the cationic price was high and the axial swelling rate increased with rising cation valence.The changes in the swelling ratio were significant at a valence of one or two.The results of this study provide further understanding of the engineering geological characteristics of black shale and the geological hazards caused by the swelling characteristics of black shale.
文摘Swell and sag drawdown significantly influence the high density polyethylene parison. Nu- merical simulations of the flow field of a HDPE melt were performed using the finite element method for the die of plastic pipe extrusion and parison formation. The constitutive equation of Carreau law was used to describe the polymer melt in the flow domain. The distributions of the velocity, shear rate, viscosity, pressure, thickness and radius are presented with Polyflow. The effect of flow rate and temperature on extrusion swell and parison sag was investigated. The results show that the thickness of the parison increases with increasing flow rate. The thickness and radius of the parison are more sensitive to changes in flow rates than to changes in temperatures.
文摘以羧甲基纤维素(CMC)、聚乙烯醇(PVA)、β-环糊精(β-CD)为原料,在碱性条件下与环氧氯丙烷(ECH)发生交联反应,制备具有高溶胀性能的CMC-PVA-β-CD三元复合水凝胶,并研究了CMC,PVA,ECH,β-CD添加量对水凝胶溶胀性能、力学性能的影响。结果表明:加入20.0 mL水,0.52 g CMC,0.20 g PVA,1.2 mL ECH,0.24 gβ-CD时,水凝胶溶胀率最高,为2 040.62 g/g,压缩应力为7.90 kPa。与PVA-CMC二元水凝胶相比,CMC-PVA-β-CD三元水凝胶的压缩应力和结晶度均有提高。该三元复合水凝胶具有较高的溶胀率和良好的力学性能,在生物医药、消毒杀菌领域具有很高的应用价值。
文摘Deep and ultra-deep reservoirs have dense matrix and high fracture pressure, which leads to high pressure and difficulty in fracturing construction. Conventional aggravated fracturing fluids have the problems of low aggravation efficiency, high friction resistance, etc., and the reduction of construction pressure cannot reach the theoretical effect. In view of the above problems, this paper adopts the weighting agent HD160 and the drag reducing agent JHFR-2 to form a new type of weighted slippery water fracturing fluid system. And the weighting performance, drag reduction performance, corrosion performance, anti-expansion performance and reservoir damage of this system were studied. The results show that the density of the system is adjustable within 1.1 - 1.6 g·cm−3, and the drag reduction rate can be up to 68% at 1.5 g·cm−3, with low corrosion rate, surface tension less than 28 mN·m−1, anti-expansion rate as high as 94.5%, and the damage rate of the reservoir permeability is less than 10%, which is of good application prospect.
