平阴县土壤中重金属元素异常成因研究

通过对平阴县周边及其西部农田区采样调查,平阴县周边元素异常具有异常衬度较高,富集系数大等特征,西部农田区异常具有各元素套合关系好,多数异常衬度不高,富集系数小的特点。结果表明,西部农田区异常是以As,Cd为主要成分的异常,元素含量与SiO2,Al2O3,Fe2O3等常量组分间具有显著的相关性,随SiO2含量的增加而降低,随Al2O3,Fe2O3含量的增加而增加,说明土壤常量组分及其所决定的土壤质地是导致异常形成的主要因素;而平阴城区异常是以S,Hg,As,Zn,Mn等元素为主的异常,是典型的人为综合因素（化工烟尘、工厂污水、生活垃圾）产生的异常。     

UHV/VHF波段SAR对次地表层土壤湿度探测与反演

首先采用一层非球形粒子植被模型,计算各波段矢量辐射传输方程Mueller矩阵一阶散射解,对比微扰法所得各波段地表粗糙面直接后向散射解,结果证明L波段植被层的散射对观测结果仍有影响,与下垫土壤粗糙表面的散射不易分离.因此,宜采用更低频率的UHF和VHF波段,对地表和次地表层能有较大的渗透深度,并可忽略植被层影响.接着,运用矢量辐射传输的3层土壤全极化Mueller矩阵解,计算UHF/VHF波段分层土壤的散射与传输,分析该两波段探测深度的差异,证实UHF波段可探测大致10-60cm深处的土壤湿度,而VHF波段探测深度能更大一些.根据第3层中土壤体湿度变化0.1时能否引起土壤表面观测的后向散射系数变化0.1dB这一判据,分析VHF波段反演第3层土壤体湿度的必要条件,证实当第2层的体湿度较小时(<0.25)才能反演层3的体温度.基于UHF/VHF两波段探测深度的差异,耗散土壤层的贡献有不同的权重,先后采用UHF和VHF,迭代法实现3层土壤湿度廓线反演.误差分析表明,该方法是有意义的.     

黄河口粉质土沉积物侵蚀性动态变化试验研究

通过一系列室内试验,研究了黄河口粉质类沉积物在循环动荷载作用后侵蚀性的变化.在试验中,采用真空预压固结装置制备重塑土样,采用液压伺服土动三轴试验机实现了不同幅值及不同振次的动荷载作用条件,并通过动三轴静态试验及贯入强度测试,测定了动荷载作用后土样强度的变化.通过水槽冲刷试验测试了不同条件的动荷载作用后,土样抗冲刷能力的变化,并进行了临界剪切应力的计算.试验结果表明:对于黄河口粉质类沉积物,动荷载作用后其强度及抗侵蚀性均降低;沉积物强度指标(不排水剪切强度、残余强度、贯入阻力)、侵蚀性指标(起动流速、临界剪切应力、冲刷率)与动荷载幅值、动荷载振次均呈现出较好的线性相关性.     

Application of matter-element model in soil nutrient evaluation of ecological fragile region

On the basis of the soil environment investigation in Da'an City, Jilin Province, China, 40 soil samples from main land use types were obtained and tested by standard method. Soil organic matter (SOM), total N (TN), total P (TP), total K (TK), available N (AN), available P (AP) and available K (AK) were chosen as the evaluation factors. A regional soil nutrient evaluation model was developed based on the matter-element model. The results show that the soil samples with nutrient grade Ⅱ-Ⅴ respectively account for 10%, 30%, 32.5% and 27.5%, and those with grade Ⅳ and Ⅴ account for 60% in all samples. The relationship between soil nutrients and land types indicates that the nutrients of farmland are relatively good, with 41.7% of soil samples with the nutrient grade Ⅳ and Ⅴ. The nutrients of saline-alkali land and sandy land are the worst, with 100% of soil samples with the nutrient grade Ⅳ and Ⅴ. And the ratios of soil samples grade Ⅳ and Ⅴ in grassland and wasteland are respectively 62.5 % and 54.55%. Generally speaking, the soil nutrients status in Da'an City is poor, 60% of soil samples are in poor and extremely poor conditions, indicating that the soil has been severely eroded. Being a relatively superior evaluation method with more accurate resuits and spatial distribution consistency, matter-element analysis is more suitable for regional soil nutrient evaluation than previous models.     

重盐碱地养殖池塘水化学特性的研究

2007年6月～10月对位于黄河下游重盐碱地凡纳滨对虾养殖池塘的水化学特性进行了研究.结果表明:(1)该地区水体的水型主要表现为ClNaⅢ,总含盐量较高,平均(2143.77±859.18)mg/L,在阴离子中,氯离子含量最高,平均(944.07±477.57)mg/L.(2)pH值较高,各池塘平均值为8.79～9.15,在整个养殖周期中水体pH＞8.5的比例占87.9%,pH＞9的比例占47.0%.(3)总硬度较高,平均为(11.96±3.69)mmol/L,极值范围为7.05～22.4mmol/L,主要表现为镁硬度.(4)水体中营养元素氮的含量较高,活性磷的含量相对较低,而总磷含量较丰富,能够满足浮游植物生长的需求.     

Dynamics and relationships of Ca, Mg, Fe in litter, soil fauna and soil in Pinus koraiensis-broadleaf mixed forest

The Liangshui Natural Reserve in Heilongjiang Province of China was selected as the study area. The authors collected the samples of forest litter （Tilia amurensis, Fraxinus mandshurica, Pinus koraiensis, Acer mono, Betula costata, and mixed litter）, soil in humus horizon （0--5cm） and soil horizon （5-20cm）, and soil macrofauna （Oligochaeta, Geophiloporpha and Juliformia） from 2001 to 2002. The role of soil macrofauna in the material cycle was analyzed through comparing the macro-element contents among various parts of the subsystems and using enrichment index （El）. The results indicate that dynamic changes of various litters are very complicated. The contents of Fe in each kind of litter increase firstly, and then decrease in the study period. The changes of macro-element contents are greater in the broad-leaf litter than in the coniferous litter, and the mixed litter is in the middle level, but the differences among them are not significant. The contents of Mg and Fe in humus are higher than those in soil, but the contents of Ca in soil are higher than that in humus. The dynamic changes of macro-element contents in soil and soil fauna are not consistent with those in litter. The diplopod presented obvious enrichment of Ca and Mg （E1〉1）, but it does not significantly enrich Fe. Earthworm has a stronger enrichment ability of Fe than diplopod and scolopendra, but E1〈1. Soil fauna can make great influences on the material cycle of the subsystems.     

Micromorphological features of Paleo-Stagnic-Anthrosols at archaeological site of Sanxingdui,China

The archaeological site of the Sanxingdui may date back as far as 5,000 years ago. The typical profiles of Palaeo-Stagnic-Anthrosols near the ancient site were selected, which aimed to identify diagnostic horizons employing methodology of soil taxonomic classification and to reveal the micromorphological properties of the paleosols. Under long-term anthropogenic mellowing, the discernible differentiation between anthrostagnic epipedon and its subhorizons as well as hydragric horizon and its subhorizons occurred in Paleo-Stagnie-Anthrosols at the archaeological site of the Sanxingdui. The mieromorphological properties diversified among each specific diagnostic subhorizon, e.g., the developed microstructure in cultivated subhorizon within anthrostagnic epipedon, closely arranged particles and considerable micropores beneficial to both of water conservation and filtration in plow subhorizon within anthrostagnic epipedon, and automorphic optical-orientation clays and calcareous corrosion in hydragric horizons. The findings above of micromorphological features related with diagnostic horizons are significant for soil taxonomic classification.     

复合加载条件下吸力式沉箱基础承载特性数值分析

吸力式沉箱基础的承载特性是海洋工程结构设施建造与设计中的一个关键问题。这种新型的深水海洋基础型式,通常承受竖向上拔荷载与水平荷载的共同作用,其工作性能与设计理论远远不能满足工程实践的需要。本文采用有限元分析方法对吸力式沉箱基础的极限承载特性进行数值计算。以大型通用有限元分析软件ABAQUS为平台,通过二次开发,数值实现了Swipe试验加载方法和固定位移比分析方法,针对不同的沉箱长径比、土的强度折减系数,探讨了沉箱基础在垂直上拔荷载和水平荷载单调联合作用下的极限承载力,通过对不同荷载组合的数值计算构造了复合加载条件下沉箱基础破坏包络面。     

氯化物型盐碱地池塘底泥中水溶性盐的分布特征

1997－1999年夏天，对位于黄河下游的氯化物型盐碱地池塘底泥中的水溶性盐进行了分析。结果表明：底泥中的含盐量，SO^2-4,Ca^2 ,Mg^2 含量是随着塘龄的增加而升高，而其余离子基本不随塘龄的增加而变化。各离子的垂直分布为“泥－土”混合层的含量较低，“水－泥”交界层含量较高。     

Impact Compressive Creep Characteristics of Simulative Soil for Deep-Sea Sediment

The impact load (equivalent impact height) applied to deep-sea sediment by a walking mining machine was first deduced by the energy conservation principle, and the simulative soil was prepared based on the deep-sea sediment collected from the Pacific C-C mining area. The self-designed impact compressive creep tests of the simulative soil were conducted under different ground stresses and impact heights, in order to determine impact compressive creep parameters using a K-H rheological model. Test results show that the impact compressive creep curves have three similar creep stages (transient creep, unstable creep, and stable creep) to static compressive creep curves, where the transient creep deformation and total deformation at the unstable creep stage decrease with the impact load. Among the three impact compressive creep parameters (K₁, K₂, β) of the simulative soil, K₁ is first increased with impact height and finally fluctuated to a certain stable value, while K₂ and β are approximately linearly increased with impact height. The maximum subsidence of the mining machine under a specific designed ground stress and walking velocity predicted by the impact compressive creep constitutive equation can be used for safety assessment of the mining machine.