Study on Consolidation of Reinforced Soft Foundationwith Two-way Drainage of Sand Well

Based on traditional consolidation theory, the soft ground settlement is calculated and one-, two-, and three-dimensional consolidation of reinforced soft foundation with sand drain is studied. The calculation method of average sand drain and the new modified method are discussed. The results can serve as a guide to subgrade design of soft ground.     

FDM for Large Strain Consolidation of Multi-Layers Super Soft Ground

Follow in precursory relating documents, several equations of one dimension Large Strain Consolidation (LSC) and consolidation coefficients were discussed firstly. Based on this, a Finite Difference Method (FDM) equation was derived, which was the physical described LSC equation with variable displacement. Moreover, the initiate and boundary condition were dispersed by FDM, and the boundary of different layers of super soft soil was disposed of continuity. Finally,nonlinear group equations of LSC FDM solution was deduced for multi layers super soft ground by repeated method, and a FDM program of 1D nonlinear LSC analysis was compiled. Finally, a case showed a satisfied analysis result by LSCFDM.     

Research On Laws of Actually Consolidation time Calculate in Saturated Soft Clay Soil by Using Vacuum-Preloading Method

Vacuum-surcharge combined preloading method have been become the most commonly used method on the dredger fill and saturated soft clay soil consolidation beside the coast.The long time of consolidation is one of this method’s most characteristics,as we always think that 3 months is the academic time.In fact,we always can’t accomplish the consolidation of siaturated soft clay soil by using vacuum-surcharge combined preloading method in 3 months because of the complex nature of the soil horizon and the effects of the construction technology.The mian mission of the article is to supply a substantial time and a reliable basis that are needed by the vacuum-surcharge combined preloading method and the construction period.The mian data sources are come from the ground treatment project of a cogeneration power plant in Zhuhai Guangzhou.We adopt the exponential curve fitting method and the method of Asaoka to count the degree of consolidation of the saturated soft clay soil.     

On Elasto-Plastic Consolidation Settlement of Saturated Soft Clay

The specific properties of soft clay are characterized by higher void ratio, lower permeability and higher compressibility, the consolidation settlement of soft clay is affected by the imposed stress history, the stress paths, the consolidation pressure and the soil properties. In this paper, the porous media theory based on the mixture theory was applied in the study on the consolidation settlement of soft clay, which was more rigorous than the conventional consolidation settlement theory and the coupling between soil and water can be taken into account in the analysis.     

保水剂对南丰蜜橘园土壤含水量的影响

【研究目的】通过探讨保水剂对南丰蜜橘园土壤的保水效应,可为其丰产优质栽培管理提供理论依据。【方法】以“杨小-26”南丰蜜橘为试验材料,探讨了RT-3005KM保水剂不同处理下南丰蜜橘园土壤含水量的变化。【结果】结果表明：0-20cm土层土壤含水量不随保水剂用量的变化而呈一定的规律性。20-40cm土层保水剂处理的土壤含水量总体高于对照并随保水剂用量的增加而增加。40-60cm与60-80cm土层保水剂处理的土壤含水量随着保水剂的增加而降低;降雨后40-60cm土层土壤含水量高于60-80cm土层,保水剂在40-60cm土层似乎有一个吸水高峰。【结论】保水剂处理在一定程度上提高了南丰蜜橘园土壤含水量。     

Reliability Analysis on Metro Shield Tunnel Segment Joint in Soft Soil

After operation of the metro, there has been increasing longitudinal nonuniform settlements of shield tunnel due to various interior and exterior factors, and then some expansion of shield tunnel segment joint develops to varying degrees, which seriously impacts on the safety of the train. Taking geometric dimension of segment, curvature radius, stiffness ratio in longitudinal, uncertainty and epistemic uncertainty into consideration, an interval Monte Carlo method has been developed which combines simulation process with the interval analysis to estimate the probability of shield tunnel segment joint failure. Finally, the interval of the failure probability is obtained. Case studies are presented to discuss the effect of different curvature radius and stiffness ratio in longitudinal on the failure probability. Herce, the control sphere of the two factors is obtained under the certain interval of the failure probability. The results provide the guidance for tunnel protection,waterproof design and construction technique of shield tunnel.     

Influence of Soft Soil Layer on Dynamic Characteristic of the Slope

The dynamic finite element method is used to analyzes the influence on dynamic characteristic of the slope by soft soil layer. The parameters which influencing the earthquake response of the slope, including the depth, the thickness, the obliquity of soft soil layer are analyzed. The influence of soft soil layer is obvious, which must be thought over in the analysis of slope stability. The thicker the soft soil layer is, the more obvious the filter and the amplitude effect is. The deeper the soft soil layer is, the more obvious the filter effect is. The filter effect of the obliquity of the soft soil layer to dynamic time history is not obvious.     

Effect of Considering Anisotropy on the Settlement of Tunnel in Soft Soil

Using different constitutive model to simulate the settlement of the fourth stage of shield excavation respectively,the models used were the anisotropic constitutive model(EVP-SCLAY1 model) and the isotropic models(MC model and MCC model),then the results with the three models and the measured datas were compared.The results show that the simulation result with the anisotropic model is more consistent with the measured results in simulating the settlement rang and surface settlement of shield excavation,and MC model prediction results are the worst.     

深圳城市绿地土壤孔隙状况与水分特征研究

为了了解深受人为活动强烈影响的城市绿地的土壤物理特性,为充分发挥其增进植物生长、涵养水源和保护城市生态环境等功能提供管理依据,以深圳城市绿地土壤为研究对象,调查分析了土壤容重、孔隙状况、土壤水分常数和水分入渗特征等物理特性。结果表明：深圳城市绿地土壤的容重较高,平均值为1.56 g/cm3。土壤总孔隙度、毛管孔隙度、通气孔隙度较小,平均值分别为41.06%、39.78%、1.27%。土壤水分入渗率变幅很大,土壤初始入渗率为0~8.47 mm/min,稳定入渗率为0~5.90 mm/min。城市公园绿地、道路绿地土壤的容重显著高于城郊菜地土壤,而土壤孔隙度、最大持水量、毛管持水量和田间持水量显著低于城郊菜地土壤;表层0~10 cm的土壤容重、最大持水量、毛管持水量和田间持水量显著低于10~20 cm土壤,土壤孔隙度显著高于10~20 cm土壤。城市绿地土壤容重与孔隙度、田间持水量、最大持水量、初始入渗率及稳定入渗率均呈显著的负相关。     

土地整理区生物-理化改良技术研究综述

对土地整理区土壤的生物、物理、化学改良技术措施进行了回顾和展望,寻找存在的不足,探讨今后的研究方向。研究表明：（1）土地整理区的生物改良措施主要是施用蚯蚓和生物菌肥,通过两者的施用可以明显的改善土壤的理化性状;（2）土地整理区的物理改良措施主要是机械深松,主要用于解决土地整理区的土壤压实问题;（3）土地整理区的化学改良措施主要是化肥的施用,用于改善土壤肥力和土壤生物学性质。现有的土地整理区生物-理化改良措施可以比较明显的改善整理区土壤质量状况,但也存在着一些不足：（1）土地整理区生物-理化的联合改良技术应用较少;（2）深松联合作业机械的通用性较差,缺乏土地整理项目区标准化的深松设备和深松深度;（3）土地整理后短期内的土壤改良技术研究较少;（4）土地整理区生物-理化改良技术与整理施工结合不够紧密。以后的土地整理区生物-理化改良技术研究需在以上4个方面进行加强。     

松辽平原高产农田土壤孔性对冻结的响应及机理研究

为了进一步深入系统研究松辽平原玉米带黑土耕作区高产田（平面型）土壤质量的管理与评价提供理论支持和借鉴,并且对黑土资源的利用与保护、为粮食的丰产增收在土壤结构理论方面具有重要的现实意义,并且对黑土资源的利用与保护、为粮食的丰产增收在土壤结构理论方面的探索,以松辽平原玉米带耕作区高产田（波浪型）与低产田（平面型）0~20 cm耕层土壤为研究对象采用田间季节性冻融过程与室内模拟冻融试验相结合的方法,研究松辽平原玉米带高产田土壤的结构性对冻结的响应,包括影响范围较深和程度,进一步阐明高产田土壤对冻结的响应机理。采用高产田与低产田对比的方法,在不同的冻结条件下,设置含水量接近5%,10%,15%,20%,25%;设置冻结频率0、2、4、6次进行室内模拟冻结实验。通过对容重、孔隙度、孔隙面积、Feret直径等指标的测定与分析,研究了不同冻结频率不同含水量,对高产田和低产田0~20 cm耕层的土壤孔隙特征的影响。结果显示：冻融循环能够显著增加松辽平原玉米带高产田与低产田0~20 cm耕层土壤孔隙的数目,高产田增加百分比为32.58%;低产田增加百分比为17.95%。显著降低了低产田0~20 cm土层范围内Feret直径和土壤的平均孔隙面积以,Feret直径由冻结前的2.31降低到冻结后的1.92,降低百分比为16.88%,低产田土壤的平均孔隙面积由冻结前的8.91降低到冻结后的4.65,降低百分率为47.81%(P<0.05)。除了土壤孔隙的成圆率外,冻融循环对高产田与低产田不同径级团聚体的孔隙数目、平均孔隙面积、平均Feret直径均有不同影响程度的差异(P<0.05)。高产田>5 mm团聚体平均孔隙面积由冻结前的37.08降低到冻结后的23.84,降低百分比为38.40%,变化差异显著(P<0.05),这是高产田与低产田相比特有的变化规律。而高产田其他粒级团聚体和低产田所有粒级团聚体的平均孔隙面积对冻结的响应不明显。高产田与低产田都有>5 mm团聚体的孔隙成圆率变化显著,高产田由冻结前的0.36降低到0.27,变化百分比为25%;低产田由冻结前的0.25增加到冻结后的0.34,变化百分比为36%,差异显著(P<0.05),这两者的变化规律截然相反,也体现高产田大粒径团聚体孔隙成圆率对冻结的响应规律有别于低产田的特殊性,以上研究结论对系统研究松辽平原玉米带黑土耕作区高产田（平面型）土壤质量的管理与评价提供理论支持有一定的意义。     

保水剂-尿素凝胶对核桃苗根际土壤微生态环境影响

为探讨保水剂与尿素的之间的最佳结合利用方式,以核桃苗为试材,通过盆栽试验研究了不施肥和保水剂(CK)、单施尿素(U)、单施保水剂(S)、保水剂-尿素混施(SUM)与保水剂-尿素凝胶(SUG)5 个处理对核桃苗的生长及其根际土壤微生态环境的影响。结果显示：较U处理而言,SUG处理的核桃苗根系分泌物中有机酸总量、氨基酸总量与总糖含量显著增加;根际土壤蔗糖酶、多酚氧化酶、脲酶与过氧化氢酶活性得到了明显的提高;同时,SUG处理亦显著提高了根际土壤微生物数量与微生物量碳、氮含量。此外,SUG处理还明显促进了核桃苗地径与株高的生长,并显著高于其他处理。与SUG处理相比,S和SUM处理对核桃苗根际土壤微生态环境的影响效果较小。综上,保水剂-尿素凝胶方式能改善核桃苗根际土壤微生态环境,增强抵御干旱胁迫能力,对其生长达到一定的促进作用。     

玉米秸秆基纤维素保水剂对土壤持水性能及冬小麦根系生长的影响

为探讨自制的玉米秸秆基纤维素保水剂(SAP)在农业生产上的应用潜力,利用扫描电镜表征了SAP吸水前后形貌变化,探究了SAP施用量对土壤持水性能和不同程度水分胁迫下冬小麦根系生长的影响.结果 表明:SAP在土壤中吸水膨胀后降低了土壤容重,土壤最大水分含量较不施SAP显著提高19.1％～67.6％,同时降低了前3天土壤水分...     

区域水土保持水土流失预测分析及实例研究

水利部对各类开发区提出推行区域水土保持评估的背景下,分析水土流失量预测方法及技术要点.以庆安开发区为例,分析东北黑土区水土流失量预测及土石方平衡估算,可以为同类区域水土保持评估水土流失量计算提供借鉴及参考.通过计算分析,得到2条结论:(1)在考虑最不利条件下,预测区域内土壤流失量结果中工业用地新增土壤流失量最大;(2)...     

砒砂岩复配土对黄瓜生长特性的影响

以黄瓜(Cucumis sativus)为研究对象,研究不同比例的风沙土与砒砂岩复配土对其生长状况与产量的影响。将风沙土与砒砂岩按照1:0、1:1、1:3、1:5、0:1、3:1、5:1的比例复配后,取温室外试验区10 cm深度的栗钙土设置为对照土样(CK)。通过比较在不同配土比例下,黄瓜株高、冠幅、结实量等生长特性的差异,探究最适宜黄瓜生长的复配比例。结果表明：（1）在风沙土与砒砂岩复配比例为1:3时,黄瓜株高81.50 cm、东西冠幅30.50 cm、南北冠幅29.50 cm、果实总质量1475.80 g、单瓜重147.58 g,除东西冠幅外,其他各项指标均呈现最优状态。（2）随着幼苗的生长,生长特性逐步呈现为线性增加的趋势,其中1:3的增长速度在各时期都是最快的,7月22日—9月16日株高增长量为73.25 cm、东西冠幅增长量为22.50 cm、南北冠幅增长量为23.00 cm。综上,风沙土与砒砂岩1:3的复配比例有利于黄瓜的生长,更能促进结实。     

Kinematics and Dynamics Analysis on the Mobile Mechanism of a Micro Piping Robot

A micro piping robot is able to help people finish tasks such as inspection inside a mini pipe. Research on the mobile mechanism of the robot is very important in the robot researching area. The kinematics and dynamics characteristics of the mobile mechanism for a planetary gears driven micro robot have been studied. The operation, the principle and the affect factors of the mobile mechanism have been discussed in detail. In order to drive the robot well, the adhesion and the power of the mobile mechanism should be increased as the influence of its autoeciousness power has been reduced.     

盐地碱蓬的耐盐机理及改良土壤机理研究进展

盐地碱蓬是盐碱地先锋植物,是目前能在含盐量为3%的土壤中生存的极少数植物之一,是重要的耐盐种质资源。其在植物耐逆机理、耐盐基因的开发利用以及土壤生态修复等方面具有极为重要的应用潜力。为了全面的了解盐地碱蓬的耐盐机理以及改良土壤的机理,本研究分别从形态学、生理生化层面以及分子水平等方面对其耐盐机理进行总结,并就盐地碱蓬影响土壤理化性质、微生物、土壤养分以及在土壤重金属、有机污染物治理等方面的研究进展进行梳理。在此基础上提出研究展望,认为应更多的关注盐地碱蓬耐逆关键基因的挖掘利用、盐地碱蓬在盐碱地植物群落演替过程的作用以及盐地碱蓬与微生物如何共同改良土壤的机理。     

不同土壤孔隙度对DGT提取Cd有效态含量的影响研究

DGT是评价重金属有效性的重要工具,但是DGT的提取受到土壤孔隙度的影响,而目前为止还缺乏相关研究。笔者采用不同磨细程度的土壤来改变土壤孔隙度,研究不同土壤孔隙度的变化对DGT提取重金属Cd有效态含量的影响。结果表明:磨细改变了土壤的孔隙度,进而影响了土壤扩散边界层,从而对土壤Cd有效态的3种计算表达形式CDGT、CE、C′E均产生了影响,且对CDGT的影响最大。但当对这些影响因素进行逐步综合考虑后,结果表明,磨细造成的孔隙度变化对土壤有效态Cd含量影响有限,其变异性均小于10%,只是在计算时应综合考虑孔隙度及扩散边界层的变化,从而减小计算造成的误差。     

关于测土配方施肥长效机制的探索与研究

本文系统全面的介绍了测土配方施肥的目的、意义,并针对现在项目实施情况所存在的一些问题,明确提出了今后工作的重点和主要做法。     

Experimental Investigation of Stabilized Soft Soil by New GSC

Soft clay is stabilized by desulphurization gypsum and steel slag-slag blended cementitious materials (GSC), which can not only reuse industrial waste and decrease second pollution, but also can conserve mineral resources and protect natural ecology. The variation of unconfined compressive strength of the clay improved by GSC with different mixing ratios and water-GSC ratio and ages was studied through the laboratory experiments. The long-term strength of stabilized soil is predicted with GSC by quasi-water-GSC ratio. The results show that the more the mixing ratios is, the better the stabilized effect of soft soil is. With increase of curing period, the strength increasing of GSC-soil is consistent with cement-soil, and it has lower strength in the early stage. When mixing ratios of GSC is more than those of cement by 3%, if the water-GSC ratio is less than those of cement, it has the higher strength than cement-soil, after 28 days. The results show that GSC stabilized soil is feasible and it can meet the demand of cure strength.