Interactive effect of nitrogen fertilizer and hydrocarbon pollution on soil biological indicators

The investigation of the impact of different forms of nitrogen fertilizer (NO₃-N and NH₄-N) on microbial parameters, enzyme activities and phytotoxicity in a petroleum-contaminated soil was evaluated by an incubation study. The tested enzymes, microbial activity and seed germination index showed different patterns in response to both petroleum and nitrogen fertilizer addition and time of incubation. The results apparently showed that the contamination of soil with petroleum has a negative effect on soil ecosystem. Nitrogen fertilizer could improve inhibition of petroleum hydrocarbons in soil. Nevertheless, nitrogen fertilizer had no significant effect on urease activity in the petroleum-contaminated soil. As compared to NO₃-N, the addition of NH₄-N to the soil resulted in a greater impact on soil performance as attested by the recovery of the soil germination capability and higher values of the respiration. The application of nitrogen fertilizer may be suggested as a good strategy for restoring soils in regions affected by the same problem.     

天山公路地质灾害决策支持地理信息系统的设计研究

天山公路由于其特殊复杂地形、地质条件及受降雨、地下水等因素,严重影响其正常通行,同时天山公路还经常受到泥石流、滑坡、崩塌、溜砂坡等地质灾害的危害,这对该公路稳定性和沿线居民的安全性都具有一定的威胁。因此,运用先进的技术手段,建立一套适应于天山公路的地质灾害决策支持信息系统就显得尤其重要。该系统的建立,对天山公路的建设改造和管理提供了强有力的支持。天山公路地质灾害决策支持地理信息系统利用强大的ArcEngine开发组件,针对新疆天山公路实际,引入RS、GIS的相关理论、方法和技术分析手段,采用相应的数学分析评价模型,对提高天山公路地质灾害防治管理水平和地质灾害的有效防治,以及评价决策等方面,都具有重要的意义。     

Phosphorus release kinetics in a soil amended with biosolids and vermicompost

Wastewater biosolids are large potential sources of macronutrients for agriculture, conservation and restoration of soils; there are, however, few studies on phosphorus (P) release in soils amended with biosolids. Biosolids and vermicomposted biosolids were tested in concentrations (5–30 g amendment kg^?1 soil) equivalent to 18–100 Mg ha^?1. Desorption of P was determined by successive extractions for 65 days. Soil P was low, and biosolid and vermicompost addition released 8 and 6 times more P, respectively, than soil alone. To describe the release of P, zero-, first- and second-order equations, simple Elovich and power functions and the parabolic diffusion law were compared based on their coefficient of determination (r ²) and standard error (SE). In all treatments, the power function and especially the parabolic diffusion law were the best fit, with 0.898–0.996 r ² and 0.022–0.732 SE. The general behavior of the kinetic parameters mostly depended on the amendment doses. Eutrophication posited to start beyond 16 mg P kg^?1 soil was more likely allayed by a maximum vermicompost dose of 50 Mg ha^?1, higher than the 36 Mg ha^?1 maximum biosolid dose. The higher vermicompost P addition and lower P release could favor gradual and longer-term P absorption by plants and may reduce leaching or runoff P losses.     

Conceptual data model and method of settlement calculation for deformation and water release from saturated soft soil

Research on the seepage deformation of saturated soft soil has resulted in many achievements based, mainly, on existing seepage-deformation control equations. In reality, however, these control equations and related parameters suffer from many problems. The conductivity coefficient in the seepage control equation and the consolidation coefficient in the consolidation equation clearly resemble each other in form. However, in existing regulations and practice, soil deformation is rarely calculated by substituting the conductivity coefficient obtained from field hydrogeological experiments for the consolidation coefficient. Similarly, seepage is seldom calculated by substituting the conductivity coefficient with the consolidation coefficient obtained from consolidation experiments. This can be attributed to the fact that the two coefficients have some obvious differences. Moreover, the settlement deformation of soil calculated using the existing seepage and consolidation models does not agree very well with the measured deformation. Also, the values calculated using different models usually deviate markedly. Research indicates that these problems derive from the fact that the seepage and consolidation equations are based on different concepts of elementary volume. This study proposes using two separate elementary volume concepts: deformation elementary volume and control elementary volume. The concepts are adopted for saturated soft soil and the results used to analyze the relationships and differences between the two concepts. Moreover, we developed a conceptual data model (CDM) for the water released from and the deformation of the saturated soil. The model discloses the differences between the consolidation and conductivity coefficients both in their physical significances and magnitudes. The inter-relationship between the two coefficients is also revealed. An analytical solution for the deformation and water released from saturated soft soil is deduced based on the CDM model and the relationship between the hydrogeological and consolidation deformation parameters is established. A physical test model for saturated soft soil under certain conditions is also designed to verify the analytical solution using a method of curve fitting. Seepage and deformation tests and case studies show that the parameters calculated using the consolidation model are in agreement with those obtained from the CDM seepage model based on the measured data for flux and settlement vs. time. Furthermore, the relationship between conductivity and consolidation coefficients is verified. The method suggested in this paper is generally applicable to problems involving the consolidation coefficient, volume compressibility, conductivity coefficient, hydraulic conductivity, and specific storage of saturated soft soil, etc. Thus, its potential applications are numerous.     

兰州富水砂卵石层土压平衡盾构渣土改良研究

兰州地铁1号线穿越(2)~(-10)和(3)~(-11)地层,主要为砂卵石层,大部分处于地下水位以下,渗透性极强。采用土压平衡(EPB)盾构施工时,除了容易出现刀盘、螺旋输送机扭矩过高,磨损严重等现象外,还极易造成螺旋输送机喷涌,酿成工程事故,因此,需要对砂卵石层进行改良以保证盾构施工的安全。采用膨润土泥浆和泡沫对砂卵石进行改良试验,得到不同改良方案渣土的塌落度、渗透系数和钢桶侧壁的摩擦系数。在塌落度满足15~20 cm要求的前提下,通过理论计算,得到了既能满足盾构和易性要求,又能使螺旋输送机保持土压平衡、防止喷涌的改良配比方案。工程实践表明,泥浆和泡沫混合掺入比分别为7%和8%的配比方案改良效果最佳,可为土压平衡盾构在兰州市富水砂卵石层施工中渣土改良和螺旋输送机防喷涌提供参考。     

吉林省西部土壤养分状况与施肥对策

本文分析、对比了吉林省西部地区土壤养分的变化状况,指出了当前施肥中存在的主要问题.根据该地区的实际情况,提出了改善土壤肥力,使其能够可持续利用的科学施肥对策.     

Effects of soil type and fertilizer on As speciation in rice paddy contaminated with As-containing pesticide

Inorganic arsenic (As) pesticides have been widely used for decades in many countries. However, insufficient data are available on the chemical speciation of inorganic arsenicals in tropical paddy soils. Inorganic As-containing pesticides were used in tropical countries, a few decades ago, however, their fate have not been studied. Hence, the objective of this study was to determine fractionation of inorganic arsenicals and to assess As lability with/without fertilizer application using a static incubation experiment. Eight soils from wet and dry regions of Sri Lanka were amended with 1,000 mg/kg arsenate for this purpose. The FT-IR and XRF results suggested that soils in the wet region were rich in Fe/Al-oxides. Paddy soils in the dry zone showed high As lability. These low-humic gley soils have low Fe/Al oxyhydroxide and alkaline pH. In contrast, the wet zone had soils with higher As retention capacity, high amounts of Fe/Al oxyhydroxide, and acidic pH. Arsenic lability increased considerably 30 days after fertilizer application. Overall, As lability was mainly influenced by soil mineralogical and chemical properties, i.e., Fe/Al oxyhydroxide, pH, organic matter, and fertilizer application.     

砂性土成拱应力释放特性的模型试验及数值模拟研究

通过室内模型试验研究了卸荷尺度及孔隙率对砂性土成拱应力释放特性的影响,并应用离散元分析软件PFC2D进一步对颗粒摩擦性质影响、成拱后应力场以及位移场变化规律和应力释放分区进行了细观研究。研究发现：（1）数值模拟对卸荷尺度影响因素的研究结果与室内试验一致,应用PFC2D研究砂性土应力释放特性是可行的。（2）应力释放区内竖向应力释放大于应力加载区,而水平应力释放小于应力加载区;侧压力系数在应力释放区内距离卸荷位置越近增量越大,而在应力加载区距离卸荷位置越近增量越小。（3）砂性土摩擦性质会减小土体成拱对应力释放以及侧压力系数变化的影响。（4）应力释放随着卸荷尺度及孔隙率的增大而增大;对于侧压力系数,在应力释放区内随着卸荷尺度或孔隙率的增大而增大,而在应力加载区随着卸荷尺度或孔隙率的增大而减小。     

实验室与田间条件下骨炭粉与海藻肥对镉污染土壤修复效果评价

本研究基于小麦、玉米、高粱籽粒及烟草烟叶镉(Cd)消减率、修复边际效率及土壤中Cd有效态含量的变化等对比了实验室与田间条件下骨炭粉与海藻肥对Cd污染农田土壤的修复效果。研究结果表明：骨炭粉与海藻肥使玉米、小麦、高粱和烟草对Cd的吸收、转运均有显著(P<0.05)降低作用;在田间条件下,骨炭粉与海藻肥对不同作物籽粒或烟叶的Cd消减率为16.2%~39.8%,可增加作物产量12.3%~38.6%。钝化剂对不同作物增产效果有一定差异,对小麦籽粒增产作用最为有效。研究发现添加钝化剂改变了Cd在土壤团聚体中的分布,使得Cd在大粒径团聚体中负载量增加,并且与对照相比,显著提高土壤pH(提高0.43~0.77),降低土壤Cd的有效性,有利于控制Cd在土壤植物系统中的迁移。总体而言,不同钝化剂的Cd污染土壤修复边际效率为3.99%~14.74%,同海藻肥相比,骨炭粉的修复边际效率较高。不同钝化剂在盆栽实验的修复效果优于田间实验的效果,可能是因为相比于田间实验,盆栽实验条件下根系的作用范围有限,钝化剂的作用效果较高。     

Minerals and design of new waste forms for conditioning nuclear waste

Safe storage of radioactive waste is a major challenge for the nuclear industry. Mineralogy is a good basis for designing ceramics, which could eventually replace nuclear glasses. This requires a new storage concept: separation-conditioning. Basic rules of crystal chemistry allow one to select the most suitable structures and natural occurrences allow assessing the long-term performance of ceramics in a geological environment. Three criteria are of special interest: compatibility with geological environment, resistance to natural fluids, and effects of self-irradiation. If mineralogical information is efficient for predicting the behaviour of common, well-known minerals, such as zircon, monazite or apatite, more research is needed to rationalize the long-term behaviour of uncommon waste form analogs.     

Toward integrated smart city: a new model for implementation and design challenges

In smart city architecture, information and communication technologies are used to improve living standards and its management by citizens and government. Most researchers have divided this structure into six main components: smart people, the smart government, smart environment, smart transportation, smart economy, and smart life. Due to the connection between smart cities and the challenges resulting from their implementation and especially its integration, there exists no perfect solution for the concept of an integrated smart city so far according to our studies. Some more general concepts such as security, ICT infrastructure, and knowledge are not seen integrative in these structures. Therefore, it seems that new sub-components and general extra-components should be added to the existing models to form an integrated structure in such a way that the executive projects are located in their proper place in this structure and create and guarantee the integration of the smart city. Therefore, the requirements engineering of the smart city can also be explained more precisely. This study presents a model of an integrated graph in such a way that besides maintaining and improving the model of the smart city and existing models, it will fully cover the integration and requirements engineering and methodologies of the smart city in the future. The present paper offers an upgraded model of a six-component smart city structure as a flexible integrated dynamic graph so that beside maintaining the features of existing smart city models, it ensures its integrity, dynamism, flexibility and performance and prevents the failure of smart operations. Due to its flexibility, adaptability and localization, the proposed model presented in this paper can create an integrated solution and facilitating the life cycle of executive systems and enable governments and communities to predict and prevent sudden events such as natural disasters, pandemics like Covid-19 and the like as well as managing and leading their target community in the best way.

     

桂林典型岩溶区土壤CO2通量及其δ13CCO2季节性特征

通过选用静态暗箱/气相色谱法,探讨桂林毛村典型岩溶区土壤CO2通量及其δ13C CO2的季节性演变规律,旨在揭示野外条件下土壤CO2及其δ13CCO2对环境因子变化的影响机制。同时野外原位监测大气温度、压强、土壤温度等环境参数来明确环境因子对土壤CO2的影响过程。结果表明:岩溶区土壤CO2通量及其δ13C CO2在季节时间尺度上呈现出相似的季节性变化规律,夏季土壤CO2通量较高,土壤δ13C CO2偏轻,且土壤CO2通量与土壤温度呈显著正相关关系。此外,夏季10 cm处土壤CO2通量明显高于0 cm,且该处δ13C CO2也偏轻于0 cm;冬季10 cm处土壤CO2通量与0 cm相差并不明显,而该处δ13C CO2却仍是偏轻于0 cm。在日时间尺度上10 cm土壤δ13C CO2明显偏轻于0 cm。      

A simple mathematical model for soil nail and soil interaction analysis

Soil nails have been widely used to stabilize slopes and earth retaining structures in many countries and regions, especially, in Hong Kong. The analysis of the interaction between a soil nail and the surrounding soil is of great interests to both design engineers and researchers. In this paper, authors present a simple mathematical model for the interaction analysis of a soil nail and the surrounding soil considering a few key factors which are soil dilation, bending of the soil nail, vertical pressure, and non-linear subgrade reaction stiffness. The lateral subgrade reaction between the soil and the soil nail is assumed to obey a hyperbolic relation. Reported test data in the literature are used to verify the present model. The contributions of the soil-nail bending on the pull-out resistance are evaluated in two case studies.     

土力学理论的发展和面临的挑战

随着社会经济的不断发展,土力学所要分析和处理问题的范围越来越广,问题本身也越来越深入和复杂。这些问题主要是由于土与环境的相互作用而产生的。为了分析和处理这些问题,经典土力学需要拓宽和深入发展,它应该包含一些新的现象和新的变量以及相应的新理论。论述了土力学所面临的三大挑战,即①没有严格、统一和完备的土力学理论;②对更具一般意义的非饱和土的行为的研究不够充分,现有的认识也不完善;③没有在多种环境作用下土的统一和完备的多场耦合理论。还论及了其他一些超出经典土力学范围的问题。     

Embedding eco-friendly and smart technology features in affordable housing for community happiness in Malaysia

GeoJournal - Two phases of study are involved in this research: first, the sales strategies for affordable houses embedded with eco-friendly and smart technology features; and second, the impact of...     

Integrated smart robot with earthquake early warning system for automated inspection and emergency response

Natural Hazards - Earthquakes as a natural hazard have caused substantial economic losses and human life loss in many countries. Taiwan, which is located on the western Circum-Pacific seismic belt,...     

土钉与土体相互作用的仿真试验分析

运用快速拉格朗日元(FLAC3D)数值法,考虑土钉的加固作用及土钉与土体的相互作用,模拟土钉支护施工过程.选择能够反映开挖特点的土的本构关系、开挖支护模拟过程及双弹簧土钉单元,建立数值分析模型.分析了基底、基坑壁土体的变形响应及土钉在开挖、使用阶段的力学响应.结果表明:①开挖引起基坑壁变形,并导致拉伸与剪切破坏;对于拉伸破坏,应使土钉长度超过滑移面;对于剪切破坏,可增大土钉在剪出口位置的密度;②开挖完毕后,各层土钉轴力沿长度方向的分布不均匀,土钉轴力最大值位置可表征潜在滑动面的位置.FLAC3D能够对基坑分步开挖及支护进行模拟,建立的数值模型能够反映土钉支护基坑的真实情况,为基坑土钉支护技术的设计与施工提供指导.     

Simple and multiple regression models for relationship between electrical resistivity and various soil properties for soil characterization

Precise determination of engineering properties of soil is essential for proper design and successful construction of any structure. The conventional methods for determination of engineering properties are invasive, costly and time-consuming. Electrical resistivity survey is an attractive tool for delineate subsurface properties without soil disturbance. Reliable correlations between electrical resistivity and other soil properties will enable us to characterize the subsurface soil without borehole sampling. This paper presents the correlations of electrical resistivity with various properties of soil. Soil investigations, field electrical resistivity survey and laboratory electrical resistivity measurements were conducted. The results from electrical resistivity tests (field and laboratory) and laboratory tests were analyzed together to understand the interrelation between electrical resistivity and various soil properties. The test results were evaluated using simple and multiple regression analysis. From the data analysis, significant quantitative and qualitative correlations have been obtained between resistivity and moisture content, friction angle and plasticity index. Weaker correlations have been observed for cohesion, unit weight of soil and effective size (D ₁₀).     

Effects of industrial by-product amendments on As,Cd and Tl retention/release in an element-spiked acidic soil

To asses the efficiency of two by-products (phosphogypsum (PG) and sugar foam (SF), rich in gypsum and calcium carbonate, respectively) in the immobilization of three toxic elements (As, Cd and Tl) in an acidic soil, batch-scale sorption and desorption experiments were conducted after 18 months of in situ amendment application. The Langmuir isotherms applied for sorption studies showed that the estimated maximum sorption capacity of the elements was highest in the SF-treated samples. The amount of element retained and the percentage of extraction after TCLP tests indicated that those samples amended with sugar foam (SF and PG + SF) had the potential to immobilize As, Cd and Tl in an acidic soil with low sorptive capacity. In addition to sorption and desorption experiments, scanning electron microscopy in back-scattered electron mode (SEM-BSE) showed the formation of Al-hydroxy polymers which provides the soil with additional sorption capacity. The three target elements were associated with the Al-hydroxy polymers, probably through direct coordination or the formation of ternary complexes. By means of statistical analysis it has been found that sorption processes of As, Cd and Tl in this soil mainly depend on the treatment, whereas desorption is an element-dependent process.     

黏土单层击实试验与制样因子研究

使用非标准击实仪进行单层击样,获取非标准击实状态下单层击实样的密度与击实功及含水率之间的关系,并进一步以得到的击实样获得其抗剪强度。发现当击实功小到一定程度时,击实密度随含水率的增大而不断增大,两者近似线性变化,无峰值出现。密度峰值对应的含水率与抗剪强度峰值对应的含水率有一个差值,其值在3.4%～5.7%之间。内摩擦角随含水率增大而减小的规律仅适合于一定的击实功。内摩擦角在较小的击实功下有峰值出现,但随着击实功的增大,内摩擦角的变化呈线性而非曲线形式。另外,针对土工室内模型试验的重塑土样制备问题,结合试验数据,给出了试验最优制样参数,并初步提供了评价指标?。