公路工程隧道透渗水病害防治技术分析

随着中国社会经济的高速增长,国家政府部门为让市民群众出行更为方便,建设了大规模的公路隧道。由于设计方案、施工技术、使用材质及其他人为因素等诸多方面的原因,目前已建成的公路隧道均出现了不同程度的病害,而其中渗漏水则成为了最为普遍的病害形式,不但影响公路隧道的整体结构与行车安全,而且还会引发电缆短路等重大安全事故,于是文章针对渗透漏水的具体问题展开了研究,并给出了一定的处理方法,希望能够提供一定的参考作用。

公路工程隧道透渗水病害防治技术分析

结合案例高速公路隧道工程实例,在了解隧道透渗水病害概况的基础上,从地质原因、防排水设施失效、设计施工因素等方面分析了隧道透渗水病害形成原因,提出了调整配置防排设施+25cm钢混凝土衬砌透渗水防治方案,并对该方案具体措施进行深入分析,望能为同类工程提供借鉴。

缝隙透渗水路面的结构层材料选择与应用设计技术研究

阐述了透渗水路面的重点设计控制指标和设计过程,从面层材料的设计选择与应用、找平层和填缝材料的设计选择、面层材料的设计选择与应用方面,探讨缝隙透渗水路面的结构层材料选择与应用设计技术,为同类透渗水路面设计应用提供技术参考。

缝隙式透渗水路面结构的载承稳定性强化设计研究

阐述缝隙式透渗水路面的强化设计原则,给出面层结构和基础层结构的强化设计思路,并通过三维有限元模拟计算,开展了预制块铺装透渗水路面的内部移位动载功效分析,相关设计原则、思路和内部移位分析成果。

长期双极反渗水透析对维持性血透患者营养状态的影响

目的:通过维持性血透(MHD)从单极反渗水透析改为双极反渗水透析,探讨双极反渗水透析对MHD营养状况的影响。方法:33例单极反渗水透析至少1年MHD患者,改为双极反渗水透析后,进行为期72个月随访,监测水质指标,比较12月和72月血清白蛋白(ALB)、人体测量、主观营养评分(SGA)等指标。结果:所有患者改为双极反渗水透析12月后,透后体重、BMI、体脂、TSF、MAMC均有增高趋势,但差异无统计学意义,白蛋白水平(p<0.05)和主观营养评分(p<0.05)得到显著改善。延长观察到双极反渗水透析72个月,透后体重和BMI又呈降低趋势,但未达到统计学差异,体脂含量减少(p<0.05),TSF减少(p<0.05),MAMC没有变化(p>0.05),白蛋白水平明显升高(p<0.05),SGA评分改善(p<0.05);双极反渗水透析72月与12月比较,白蛋白水平无变化(p>0.05),MAMC没有变化(p>0.05),SGA降低(p<0.05),TSF减少(p<0.05)、体脂含量减少(p<0.05)。结论:双极反渗水改进了透析液水质,可改善MHD营养状态。

双反渗水透析对患者营养状态及贫血的影响

目的通过维持性血液透析患者(MHD)从单反渗水透析改为双反渗水透析后,探讨双反渗水透析对维持性血液透析患者营养状况的影响。方法对48例透析龄>1年的MHD患者进行为期12个月随访,监测水质指标,血清清蛋白、人体测量、主观营养评分(SGA)、Hb、重组红细胞生成素剂量、血压等。结果双反渗水透析12个月后,干体重、BMI、体脂、瘦体重、肱三头肌皮褶厚度(TSF)、中臂肌肉周径(MAMC)均有增高趋势,但差异无统计学意义;主观营养评分(SGA)、清蛋白(ALB)在12个月后得到显著改善。结论双反渗水改进了透析液水质,可以改善MHD营养状态。

地表洪流引发的透渗混凝土路面塞堵过程模拟实验分析

本研究以透渗混凝土塞堵模拟室内实验的方式,对地表洪流引发的透渗混凝土路面塞堵过程开展专题模拟实验分析,探究透渗混凝土孔隙率、塞堵材料的颗粒大小和地表径流速率对透渗混凝土孔隙塞堵引发的路面透渗性下降的影响,为优化实现新型透渗混凝土路面工程应用提供研究和技术参考。

Macroscopic and microscopic mechanical behavior and seepage characteristics of coal under hydro-mechanical coupling

Understanding the physical,mechanical behavior,and seepage characteristics of coal under hydro-mechanical coupling holds significant importance for ensuring the stability of surrounding rock formations and preventing gas outbursts.Scanning electron microscopy,uniaxial tests,and triaxial tests were conducted to comprehensively analyze the macroscopic and microscopic physical and mechanical characteristics of coal under different soaking times.Moreover,by restoring the stress path and water injection conditions of the protective layer indoors,we explored the coal mining dynamic behavior and the evolution of permeability.The results show that water causes the micro-surface of coal to peel off and cracks to expand and develop.With the increase of soaking time,the uniaxial and triaxial strengths were gradually decreased with nonlinear trend,and decreased by 63.31%and 30.95%after soaking for 240 h,respectively.Under different water injection pressure conditions,coal permeability undergoes three stages during the mining loading process and ultimately increases to higher values.The peak stress of coal,the deviatoric stress and strain at the permeability surge point all decrease with increasing water injection pressure.The results of this research can help improve the understanding of the coal mechanical properties and seepage evolution law under hydro-mechanical coupling.

Practice and analysis of recycling non-drinking water from air-condition and reverse-osmosis system into rainwater collection system

This paper is based on the rainwater collection project in the retrofit of the Dongyi teaching block in Zhejiang University Xixi Campus.The analysis incorporates the local meteorological data, recycling water utilization, and precipitation adjustment.The rainwater collection system in this program also adds the condensation water from the heating, ventilation and air conditioning （ HVAC） system and the concentration from the reverse-osmosis system used for watering greens and supplying waterscapes.By calculating, the quantity of the HVAC condensation water in summer is 3.48 m3/d, and the quantity of the reverse-osmosis concentrated water is 198 to 396 L/d.This method solves the water shortage caused by high evaporation in summer and low precipitation in winter.Supported by empirical monitoring data, the proposed method significantly increases the economic efficiency of the system during the summer period.

Numerical simulation of dynamic pore pressure in asphalt pavement

For studying the driving role of dynamic pressure in water-induced damage of asphalt pavement, based on the fast Lagrangian finite difference method and Biot dynamic consolidation theory, fluid-solid coupling analysis of the pavement is conducted considering asphalt mixtures as porous media. Results reveal that the development and dissipation of the dynamic pore pressure are coinstantaneous and this makes both the positive and negative dynamic pore pressure and seepage force alternate with time. Repetitive hydrodynamic pumping and sucking during moisture damage is proved. The dynamic pore pressure increases with vehicle velocity. Effective stress and deflection of pavement decrease due to the dynamic pore water pressure. However, the emulsification and replacement of the asphalt membrane by water are accelerated. The maximum dynamic pore pressure occurs at the bottom of the surface course. So it is suggested that a drain course should be set up to change the draining condition from single-sided drain to a two-sided drain, and thus moisture damage can be effectively limited.

Relation between relative permeability and hydrate saturation in Shenhu area, South China Sea

Nuclear magnetic resonance measurements in hydrate-bearing sandstone samples from the Shenhu area, South China Sea were used to study the effect of gas hydrates on the sandstone permeability. The hydrate-bearing samples contain pore-filling hydrates. The data show that the pore-filling hydrates greatly affect the formation permeability while depending on many factors that also bear on permeability; furthermore, with increasing hydrate saturation, the formation permeability decreases. We used the Masuda model and an exponent N = 7.9718 to formulate the empirical equation that describes the relation between relative permeability and hydrate saturation for the Shenhu area samples.

A simulation study of formation permeability as a function of methane hydrate concentration

We modeled and studied the permeability of methane hydrate bearing formations as a function of methane hydrate concentration by artificially varying the T2 distribution as well as using a tube-sphere model.We varied the proportion of irreducible and movable water as well as the total porosity associated with the T2 distribution and found the normalized permeability as a function of methane hydrate concentration is dependent of these variations.Using a tube-sphere model,we increased the methane hydrate concentration by randomly placing methane hydrate crystals in the pore spaces and computed the permeability using either the Schlumberger T2 relaxation time formula or a direct calculation based on Darcy＇s law assuming Poiseuille flow.Earlier experimental measurements reported in the literature show there is a methane hydrate concentration range where the permeability remains relatively constant.We found that when the Schlumberger T2 relaxation time formula is used the simulation results show a curve of normalized permeability versus methane hydrate concentration quite close to that predicted by the Masuda model with N = 15.When the permeability was directly calculated based on Darcy＇s law,the simulation results show a much higher normalized permeability and only show a trend consistent with the experimental results,i.e.,with a permeability plateau,when the methane hydrate crystals are preferentially placed in the tubes,and the higher the preferential probability,the larger the range where the permeability has a plateau.

The Unsaturated Hydraulic Parameters for Aeolian Sand

The water characteristic curve for aeolian sand in two processes of wetting and drying was obtained by the negative water column technique.The values of fitting parameters were calculated according to Van Genuchten formula and the parameters that characterized the prosperities of aeolian sand such as the unsaturated infiltration coefficient and specific water capacity were obtained.The results showed that the water characteristic curve for aeolian sand in wetting process had greater hysteresis quality than ...

Effect of Mulberry(Morus alba Linn) on Soil and Water Conservation

Rational development and utilization of hilly land is an effective measure for raising land productivity, developing countryside economy, increasing peasants＇ income, conserving soil and water, and improving eco-environment. The growth and root distribution of mulberry trees were studied. Various indexes including soil physical characters and hydrological status, water infiltration rate, water and soil loss and soil erosion amount were tested. The results indicated that mulberry trees had the effects of intercepting rainfall, improving soil infiltration rate, decreasing soil erosion amount, and conserving water and soil

Changes of Water Status and Different Responses of Osmoregulants in Jatropha Curcas L. Seedlings to Air-drought Stress

[Objective] The study aimed to investigate the changes of water status and different responses of osmoregulants during air-drought stress,to better understand mechanisms of drought resistance in Jatropha Curcas L. [Methods] The 12-day-old J. curcas seedlings were held in a climate chamber at 25/20 ℃（day/night）,16 hours illumination,and 75% of relative humidity for air-drought treatment,and the changes of water potential,osmotic potential and the content of soluble sugar,proline,betaine were measured. [Results] Water potential and osmotic potential in leaves of J. curcas seedlings dropped significantly,pressure potential lost during air-drought stress,and the contents of osmoregulants soluble sugar,proline and betaine rose significantly to different extent in the leaves and stems. [Conclusion] Osmoregulants in the leaves and stems respond differently to air-drought stress,and in general leaves are much more responsive to the drought than stems of J. curcas seedlings.

The Study of Dipivefrin Hydrochloride Ophthalmic Gel

Dipivefrin hydrochloride ophthalmic gel was prepared and the release test and the isolated cornea permeation test of the formulation in vitro were investigated. The release test of the formulation was studied by using permeable membrane. The content and the release amount of Dipivefrin hydrochloride from the gel base were measured by high performance liquid chromatography. The cornea permeation test of the formulation was studied by using isolated rabbit corneas. The formulation release behavior in vitro followed the first-order kinetic equation. The release amount of Dipivefrin hydrochloride raised significantly with less polymer in the formulation. The cornea permeation behavior of the drug in vitro followed the first-order kinetic equation. The eye irritancy of Dipivefrin hydrochloride gel is lower than that of eyedrops.

An Improved Frequency Domain Technique for Determining Soil Water Content

For many years a soil water content sensor with low cost, reliability and sufficient accuracy has been desirable. Thus, an improved measurement method based on the frequency domain (FD) principle for determining soil water content was considered. Unlike other measurement principles, a new measurable index, η, which was independent of the output impedance and the amplitude of the oscillator while relying on the electrical impedance of a multi-pin probe, was pro- posed. Moreover, a model for processing the impedance of the multi-pin soil probe was developed, and several important electrical parameters for establishing their operating ranges applicable to this probe were evaluated. In order to confirm the theoretical analysis, an experiment was conducted with a 4-pin probe. Using the developed model, the relationship between the proposed index η and soil volumetric water content was shown to be linear (R2 = 0.9921). Thus, as the measurable index, η seemed satisfactory.

An Analytical Method for Relationship Between Hydraulic Diffusivity and Soil Sorptivity

A simple method was developed to relate soil sorptivity to hydraulic diffusivity and water absorption experiments were conducted utilizing one-dimensional horizontal soil columns to validate the relationship. In addition, an estimation method for hydraulic diffusivity with disc infiltrometer was developed. The results indicated a favorable fit of the theoretical relation to the experimental data. Also, the experiment with disc infiltrometer for estimating the diffusivity showed that the new method was feasible.

Water and Heavy Metal Transport in Roadside Soils

Roads with very high traffic loads in regions where soils are low in both pH and sorption capacity might be a source of percolation water loaded with heavy metals. Looking at some "worst case" scenarios, this study focused on the input of traffic related pollutants and on Pb, Cd, Cu, Zn, Ni and Cr concentrations in the soil matrix and soil solution, respectively. The analysis also included pH and electrical conductivity and at some sites DOC. The investigations were carried out on sandy soils with more or less low pH values at four motorway sites in Germany. The average of daily traffic was about 50 000 up to 90 000 vehicles. Soil pore water was collected in two soil depths and at four distances from the road. The pH in general decreased with increasing distance from the roadside. The elevated pH near the roadside was presumably caused by deposition of dust and weathering residues of the road asphalt, as well as by infiltration of salt that was used during winter time. At these road sites, increased heavy metal concentrations in the soil matrix as well as in the soil solution were found. However, the concentrations seldom exceeded reference values of the German Soil Protection Act. The soil solution concentrations tended to increase from the road edge to 10 m distance, whereas the concentration in the soil matrix decreased. Elevated DOC concentrations corresponded with elevated Cu concentrations but did not substantially change this tendency. High soil water percolation rates were found near the roads. Thus, even low metal concentrations of percolation water could yield high metal loads in a narrow area beside the road.

Chloride ion penetration into concrete under hydraulic pressure

The lining concrete of subsea tunnel services under combined hydraulic pressure, mechanical and environmental loads. The chloride ion and water penetrations into concrete under hydraulic pressure were investigated. The experimental results indicate that the water penetration depth, chloride ion transportation depth, and the concentration of chloride ion ingression into concrete increase with raised hydraulic pressure and hold press period. But the chloride ion transportation velocity is only 53% of that of water when concrete specimens are under hydraulic pressure. The chloride transportation coefficient of concrete decreases with hold press period as power function. And that would increase 500% 600% in chloride transportation coefficient when the hydraulic pressure increases from 0 to 1.2 MPa. The hydraulic pressure also decreases the bound chloride ion of concrete to about zero. Besides, the low water-cementitions materials and suitable content of mineral admixture(including fly ash and slag) improve the resistance capacity of chloride penetration, and binding capacity of concrete under hydraulic pressure.