采用足尺加速加载试验模拟和研究路面长期服役性能,是世界公认的最为高效、对自然和荷载耦合作用仿真度最高的技术手段,是路面设计理论发展的重要支撑.面向新一代长寿命路面技术目标,充分发挥足尺加速加载试验的优势,深入揭示荷载与环...采用足尺加速加载试验模拟和研究路面长期服役性能,是世界公认的最为高效、对自然和荷载耦合作用仿真度最高的技术手段,是路面设计理论发展的重要支撑.面向新一代长寿命路面技术目标,充分发挥足尺加速加载试验的优势,深入揭示荷载与环境耦合作用下的复杂路面结构行为机理,是革新路面设计方法的有效途径之一.第S54次香山科学会议"中国长寿命路面关键科学问题及技术前沿"的议题之一"路面足尺试验的目标与科学问题",即立足国内外足尺加速加载试验研究的主要经验与贡献,对研究目标和科学问题进行了讨论,进一步明确了该领域的发展方向和研究重点.本文通过对我国首条足尺加速加载路面试验环道RIOHTrack(Research Institute of Highway MOT Track)设计理念及研究进展的介绍,论述了长期持续观测积累的科学数据对于认识、发现路用性能演化规律的重要性,以及由现象学层面特征和差异出发,遵循现象发现-理论解析-实践验证的路面工程研究方法论,在非线性力学分析体系、多元仿真模型构建等研究方面取得的主要进展.展开更多
Expansive soil is sensitive to dry and wet environment change. And the volume deformation and inflation pressure of expansive soil may induce to cause the deformation failure of roadbed or many other adverse effects. ...Expansive soil is sensitive to dry and wet environment change. And the volume deformation and inflation pressure of expansive soil may induce to cause the deformation failure of roadbed or many other adverse effects. Aimed at a high-speed railway engineering practice in the newly built Yun-Gui high-speed railway expansive soil section in China, indoor vibration test on a full-scaled new cutting subgrade model is carried out. Based on the established track-subgrade-foundation of expansive soil system dynamic model test platform, dynamic behavior of new cutting subgrade structure under train loads coupling with extreme service environment(dry, raining, and groundwater level rising) is analyzed comparatively. The results show that the subgrade dynamic response is significantly influenced by service conditions and the dynamic response of subgrade gradually becomes stable with the increasing vibration times under various service environment conditions. The vertical dynamic soil stress is related with the depth in an approximate exponential function, and the curves of vertical dynamic soil stress present a "Z" shape distribution along transverse distance. The peak value of dynamic soil stress appears below the rail, and it increases more obviously near the roadbed surface. However, the peak value of dynamic soil stress is little affected outside 5.0 m of center line. The vibration velocity and acceleration are in a quadratic curve with an increase in depth, and the raining and groundwater level rising increase both the vibration velocity and the acceleration. The vertical deformations at different depths are differently affected by service environment in roadbed. The deformation of roadbed increases sharply when the water gets in the foundation of expansive soil, and more than 60% of the total deformation of roadbed occurs in expansive soil foundation. The laid waterproofing and drainage structure layer, which weakens the dynamic stress and improves the track regularity, presents a positive effect on the control deform展开更多
This paper involves a series of destructive full-scale load tests on long bored piles instrumented with strain gauges along the shafts,including two compression and two tension loading tests.The load-displacement resp...This paper involves a series of destructive full-scale load tests on long bored piles instrumented with strain gauges along the shafts,including two compression and two tension loading tests.The load-displacement response,axial force,skin friction,and the thresholds of the slip displacement for fully mobilizing the skin resistances in different soils are discussed.Moreover,the theoretical solution for estimating the pile tip settlement under compression was adopted to analyze the test results.It was found that the measured skin frictions for the piles under compression were about 6% to 42% higher than the estimated values of the cone penetration tests(CPTs),whereas the measured skin frictions in the uplift cases were about 16% to 50% smaller than the estimated values.In addition,the average limited skin frictions for the tension piles were about 0.36 to 0.78 times the average ultimate skin frictions for the piles under compression.It also can be indicated that the skin friction along the pile depth approached the limited state,and decreased from a peak value with increasing loads.展开更多
Shanghai Changjiang Tunnel, 15 m in diameter, is one of the world＇s largest shield-driven tunnels in diameter. Tongji University has recently carried out a test on the full-scale three-ring lining structure of Changj...Shanghai Changjiang Tunnel, 15 m in diameter, is one of the world＇s largest shield-driven tunnels in diameter. Tongji University has recently carried out a test on the full-scale three-ring lining structure of Changjiang Tunnel. This paper introduces the testing processes, including loading apparatuses, test contents, test cases, etc., and makes comparison with other shield lining structure tests conducted before, and finally gives some evaluations on the design of the tunnel.展开更多
Membrane bioreactors(MBRs)have been and will continue playing an important role in industrial wastewater treatment and reuse in China.The sustainable development of MBR technology in its mature-application stage requi...Membrane bioreactors(MBRs)have been and will continue playing an important role in industrial wastewater treatment and reuse in China.The sustainable development of MBR technology in its mature-application stage requires reciprocal interactions between engineering and research participants.Thus,in this study,a total of 182 large-scale MBR projects treating industrial wastewater(with individual treatment capacities5000 m3d1)commissioned and under construction from 2003 to 2019 were analyzed comprehensively.Fast growth of the cumulative treatment capacity was observed,with extension to diverse industries,and the super large-scale was enhanced recently.The treatment processes,pollutant removal efficiencies,and actual operational parameters were summarized regarding the particularity of industrial wastewater compared to municipal wastewater.Economic features including the total investment costs of the projects,their total footprint,and their operational energy consumption were analyzed as well.A vigorous MBR market has formed in China with the fast development of membrane elements and engineering suppliers,continuously increasing official oriented projects,and responsive and innovative business modes.MBR technology has been mostly applied in specific economic zones and water-deficient areas,but its widespread use all over China is foreseeable considering the vast future market for industrial wastewater treatment and recycling.The policy–economy and market–technology driving forces revealed that MBR is consistent with the national development demand.According to the survey and analysis,prospective development in both engineering and research aspects of MBR is proposed to maintain its competitive edge.展开更多
重点研究厌氧UASB反应器污泥沼气中产生的气态磷化氢、结合态磷化氢沿高度分布以及磷平衡.结果表明,沼气中平均磷化氢浓度为1.94～17.92ngPH3/m3;反应器上空大气中气态磷化氢浓度约为0.09～0.16ng PH3/m3.反应器周围100m大气中未测到磷...重点研究厌氧UASB反应器污泥沼气中产生的气态磷化氢、结合态磷化氢沿高度分布以及磷平衡.结果表明,沼气中平均磷化氢浓度为1.94～17.92ngPH3/m3;反应器上空大气中气态磷化氢浓度约为0.09～0.16ng PH3/m3.反应器周围100m大气中未测到磷化氢.污泥结合态磷化氢浓度及沿高度分布随生产季节差异较大,4月份测得结合态磷化氢浓度较高(19.14～106.3 ngPH3/kg湿泥),沿高度呈波浪形走势;10月份浓度仅为4月份的9%～74%(9.05～27.52 ng PH3/kg湿泥),呈顶部和底部浓度高中间低的趋势,这可能与10月份污染物浓度低流量高有关.反应器顶部溢流区污泥中结合态磷化氢浓度高达100.1 ng PH3/kg湿泥(4月份).由于溢流区阳光可以直射而且与空气直接接触,这意味着很可能存在另一种磷化氢生成新机制,即不同于厌氧微生物生成磷化氢. 磷平衡研究发现,每天通过沼气损失的P量为4.5～46.6μg P,占总磷去除量的(0.434～4.25)×10-6‰.每天以污泥结合态磷化氢方式损失的磷量可估算为42.03～146.7μgP,占废水总磷去除量的(3.82～14.1)×10-6‰.排泥损失的总磷量为4.45 kg P/d,占废水总磷去除量的43%.废水通过厌氧生成磷化氢除磷可行性极低.展开更多
文摘采用足尺加速加载试验模拟和研究路面长期服役性能,是世界公认的最为高效、对自然和荷载耦合作用仿真度最高的技术手段,是路面设计理论发展的重要支撑.面向新一代长寿命路面技术目标,充分发挥足尺加速加载试验的优势,深入揭示荷载与环境耦合作用下的复杂路面结构行为机理,是革新路面设计方法的有效途径之一.第S54次香山科学会议"中国长寿命路面关键科学问题及技术前沿"的议题之一"路面足尺试验的目标与科学问题",即立足国内外足尺加速加载试验研究的主要经验与贡献,对研究目标和科学问题进行了讨论,进一步明确了该领域的发展方向和研究重点.本文通过对我国首条足尺加速加载路面试验环道RIOHTrack(Research Institute of Highway MOT Track)设计理念及研究进展的介绍,论述了长期持续观测积累的科学数据对于认识、发现路用性能演化规律的重要性,以及由现象学层面特征和差异出发,遵循现象发现-理论解析-实践验证的路面工程研究方法论,在非线性力学分析体系、多元仿真模型构建等研究方面取得的主要进展.
基金Projects(51478484,51308551,51678571)supported by the National Natural Science Foundation of ChinaProject(2016zzts063)supported by Fundamental Research Funds for the Central Universities,China
文摘Expansive soil is sensitive to dry and wet environment change. And the volume deformation and inflation pressure of expansive soil may induce to cause the deformation failure of roadbed or many other adverse effects. Aimed at a high-speed railway engineering practice in the newly built Yun-Gui high-speed railway expansive soil section in China, indoor vibration test on a full-scaled new cutting subgrade model is carried out. Based on the established track-subgrade-foundation of expansive soil system dynamic model test platform, dynamic behavior of new cutting subgrade structure under train loads coupling with extreme service environment(dry, raining, and groundwater level rising) is analyzed comparatively. The results show that the subgrade dynamic response is significantly influenced by service conditions and the dynamic response of subgrade gradually becomes stable with the increasing vibration times under various service environment conditions. The vertical dynamic soil stress is related with the depth in an approximate exponential function, and the curves of vertical dynamic soil stress present a "Z" shape distribution along transverse distance. The peak value of dynamic soil stress appears below the rail, and it increases more obviously near the roadbed surface. However, the peak value of dynamic soil stress is little affected outside 5.0 m of center line. The vibration velocity and acceleration are in a quadratic curve with an increase in depth, and the raining and groundwater level rising increase both the vibration velocity and the acceleration. The vertical deformations at different depths are differently affected by service environment in roadbed. The deformation of roadbed increases sharply when the water gets in the foundation of expansive soil, and more than 60% of the total deformation of roadbed occurs in expansive soil foundation. The laid waterproofing and drainage structure layer, which weakens the dynamic stress and improves the track regularity, presents a positive effect on the control deform
基金Project(No.51078330)supported by the National Natural Science Foundation of China
文摘This paper involves a series of destructive full-scale load tests on long bored piles instrumented with strain gauges along the shafts,including two compression and two tension loading tests.The load-displacement response,axial force,skin friction,and the thresholds of the slip displacement for fully mobilizing the skin resistances in different soils are discussed.Moreover,the theoretical solution for estimating the pile tip settlement under compression was adopted to analyze the test results.It was found that the measured skin frictions for the piles under compression were about 6% to 42% higher than the estimated values of the cone penetration tests(CPTs),whereas the measured skin frictions in the uplift cases were about 16% to 50% smaller than the estimated values.In addition,the average limited skin frictions for the tension piles were about 0.36 to 0.78 times the average ultimate skin frictions for the piles under compression.It also can be indicated that the skin friction along the pile depth approached the limited state,and decreased from a peak value with increasing loads.
文摘Shanghai Changjiang Tunnel, 15 m in diameter, is one of the world＇s largest shield-driven tunnels in diameter. Tongji University has recently carried out a test on the full-scale three-ring lining structure of Changjiang Tunnel. This paper introduces the testing processes, including loading apparatuses, test contents, test cases, etc., and makes comparison with other shield lining structure tests conducted before, and finally gives some evaluations on the design of the tunnel.
基金supported by the Beijing Natural Science Foundation(L182044)the Ministry of Industry and Information Technology(MIIT)Project(2017LSZZ001-003)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(2019172).
文摘Membrane bioreactors(MBRs)have been and will continue playing an important role in industrial wastewater treatment and reuse in China.The sustainable development of MBR technology in its mature-application stage requires reciprocal interactions between engineering and research participants.Thus,in this study,a total of 182 large-scale MBR projects treating industrial wastewater(with individual treatment capacities5000 m3d1)commissioned and under construction from 2003 to 2019 were analyzed comprehensively.Fast growth of the cumulative treatment capacity was observed,with extension to diverse industries,and the super large-scale was enhanced recently.The treatment processes,pollutant removal efficiencies,and actual operational parameters were summarized regarding the particularity of industrial wastewater compared to municipal wastewater.Economic features including the total investment costs of the projects,their total footprint,and their operational energy consumption were analyzed as well.A vigorous MBR market has formed in China with the fast development of membrane elements and engineering suppliers,continuously increasing official oriented projects,and responsive and innovative business modes.MBR technology has been mostly applied in specific economic zones and water-deficient areas,but its widespread use all over China is foreseeable considering the vast future market for industrial wastewater treatment and recycling.The policy–economy and market–technology driving forces revealed that MBR is consistent with the national development demand.According to the survey and analysis,prospective development in both engineering and research aspects of MBR is proposed to maintain its competitive edge.
文摘重点研究厌氧UASB反应器污泥沼气中产生的气态磷化氢、结合态磷化氢沿高度分布以及磷平衡.结果表明,沼气中平均磷化氢浓度为1.94～17.92ngPH3/m3;反应器上空大气中气态磷化氢浓度约为0.09～0.16ng PH3/m3.反应器周围100m大气中未测到磷化氢.污泥结合态磷化氢浓度及沿高度分布随生产季节差异较大,4月份测得结合态磷化氢浓度较高(19.14～106.3 ngPH3/kg湿泥),沿高度呈波浪形走势;10月份浓度仅为4月份的9%～74%(9.05～27.52 ng PH3/kg湿泥),呈顶部和底部浓度高中间低的趋势,这可能与10月份污染物浓度低流量高有关.反应器顶部溢流区污泥中结合态磷化氢浓度高达100.1 ng PH3/kg湿泥(4月份).由于溢流区阳光可以直射而且与空气直接接触,这意味着很可能存在另一种磷化氢生成新机制,即不同于厌氧微生物生成磷化氢. 磷平衡研究发现,每天通过沼气损失的P量为4.5～46.6μg P,占总磷去除量的(0.434～4.25)×10-6‰.每天以污泥结合态磷化氢方式损失的磷量可估算为42.03～146.7μgP,占废水总磷去除量的(3.82～14.1)×10-6‰.排泥损失的总磷量为4.45 kg P/d,占废水总磷去除量的43%.废水通过厌氧生成磷化氢除磷可行性极低.
