Genetic Algorithm for the Consolidation Coefficient Evaluation

The deformation and stress induced by the loading of building on the foundation will cause the settlement and incline.If the foundation settlement isn't a uniform one,it will decline and affect the safety of the building.The consolidation coefficient is the main factor for the settlement of foundation.At present,the method for the consolidation coefficient such as logarithm of time and square root of time methods couldn't overcome the jamming.However the Genetic Algorithm can diminish the jamming and a precise result can be gained.     

流固耦合的多元结构深厚覆盖层透水地基的力学特性

深厚覆盖层多元结构坝基在渗流过程中各土层力学差异明显，分析时关注的具体问题也不尽相同，需要深入研究。基于比奥固结理论，考虑土体的非线性流变以及土体固结变形过程中孔隙度、渗透系数、弹性模量及泊松比的变化；借助ADINA流固耦合模块来模拟西藏达嘎水电站坝基渗流场与应力场耦合过程，分析各层力学特性及相互作用。研究表明，透水性较强的表层土体是渗流主要通道，也是渗流进出区和沉降变形体现区，应在上游采取措施提高其压缩模量，下游区域增设反滤层和排水设施；坝基中的粉细砂层是坝基沉降的主要原因，对坝基沉降起主导作用，同时应注意其液化特性对坝基的不利影响；坝基中的承压含水土层对下游上部结构产生向上顶托力，若位置较深，则破坏性较小；坝基深部土层对整个坝基的渗流破坏影响较小，但对沉降和渗流量的影响不可忽视；表层砂卵砾石层和粉细砂层的渗透系数相差较小时，土层间不会发生接触冲刷。此外，还发现坝基孔隙水压力在快速衰减阶段被消散，期间土体固结较快。垂直防渗墙能有效降低渗透坡降和渗流量，将坝基沉降变形控制在防渗墙上游区域，但上游坝基变形对防渗墙产生较大的水平推力，应加大防渗墙尺寸或者采用辅助渗控措施。     

基坑开挖及降水对坑外地表沉降的影响

考虑降水、支护结构变形以及基坑隆起3个因素引起的基坑周围土体的沉降,根据降水引起土体沉降的机理,运用修正的分层总和法单独计算出由降水引起的周围土体沉降。通过研究基坑开挖引起坑外土体沉降的规律,推导出由基坑开挖引起的坑外土体沉降理论公式。把降水引起的沉降及基坑开挖引起的沉降进行叠加,加入修正系数,最终以简化的理论公式合理地计算出基坑周围土体沉降。具体工程验证表明,推导的理论解析解与实测数据十分接近,能有效预估基坑周围土体沉降,为施工方案编制提供可靠的理论依据,最大限度减少基坑施工对周围环境的影响。     

Contrast Analysis of the Reinforcement Effect of Pile-Net Composite Foundation

To investigate the effect of consolidation soft soil, three groups of model tests were designed. The first group was PVC pile-net composite foundation, the second was pile-cap-net composite foundation, and the third was PVC and sand pile composite foundation. Butter was coated and plastic membrane was covered on inner side wall of model cast to reduce border effect. The gauges were glued with epoxy on the surface of the model with PVC piles and geogrids to measure the stress of PVC piles and geogrids. Soil pressure cells were installed in the middle of piles and the top of the sand piles, and dial indicators were installed in the middle of road and road shoulder to measure deformations. It is that shown: 1) as for the distribution of the road settlement and the differential settlement, the settlements of the third group are the largest and those of the second group are the least; 2) in terms of the stress ratio of PVC pile and soil, the values of the first group and the third group are similar, while the value of the second group is much larger; 3) the change of geogrid strain is disorderly. There are periodic peaks in the strain of geogrid of pile top and periodic troughs in the soil between the piles. The geogrid strain of the second group measured in the corresponding spot is much larger than those of the other two groups. The results of three groups of tests illustrate that if the condition is permitted, it would be the best to adopt the scheme of pile-cap-net composite foundation, which has better reinforcement effect for soft soil.     

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.     

On the Pattern of Rural Human Settlement Environment Construction in Yunnan''s Mountain Region

The laggard status of rural human settlement environment of mountain region in Yunnan Province affected the balanced development between city and countryside, so accelerating its construction is the urgent need of rural development. In this paper, the characteristics and realistic influence of traditional pattern of rural human settlement environment construction in Yunnan mountain region are expounded. Moreover, it puts forward the construction pattern, which depends on the development of small towns by analyzing the connection among natural environment characteristics, society and economy innovation and the pattern of human settlement environment construction. At last, several advices are brought forward for the actual action of rural human settlement environment construction in future.     

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.     

Numerical Simulation and Field Monitoring Research of Reinforcement Range of Soft Ground on One Side Road Widening Project

As one of common reinforcement measure, cement mix pile is widely used in soft ground treatment of road widen project, while relevant studies on reinforcement range is insufficient. According to the one side road widening project, the cross-section of deep soft ground is analyzed. When fill is simplified as trapezoid load, the conclusion that reinforcement depth of cement mix pile should greater than load breadth can be gained by addition stress distribution. Based on the numerical simulation of different reinforcement measures, the slope stability, road settlement and horizontal deformation are influenced greatly by reinforcement range. Comparison research indicates that when the soft ground from slope toe to road shoulder is strengthened, the improvement effect is obvious. The numerical simulation and field monitoring resules show that reinforcement measure is suitable. Meanwhile, this study can provide reference to similar project.     

600 MPa高强钢筋与混凝土的粘结锚固性能试验研究

为研究600 MPa高强钢筋与混凝土粘结锚固性能，设计了72个棱柱体试件进行拉拔试验，对600 MPa高强钢筋粘结锚固的破坏形态及粘结应力分布进行分析，通过建立基本粘结滑移关系及位置函数，确定600 MPa高强钢筋在混凝土结构中的粘结滑移本构关系。采用一次二阶矩法进行可靠度分析，提出锚固长度设计建议。研究表明：600 MPa高强钢筋粘结锚固的破坏形态及粘结应力分布与普通钢筋类似且粘结锚固性能良好，《混凝土结构设计规范》（GB 50010—2010）基本锚固长度计算公式依然适用于600 MPa高强钢筋。     

High-Speed Railway CFG Pile Composite Foundation Settlement Influence Factors Analysis

Because of high bearing capacity and small settlement of CFG pile, CFG pile have been used widely in foundation treatment of engineering construction, but it has applicant in high-speed railway roadbed only in the initial stage. In this paper, based on the project of Beishahe of Hada high-speed rail, simulated with the finite element model by ADINA by changing the parameters of CFG pile and roadbed height in the situation of permafrost and unpermafrost of foundation, obtained the relationship of parameters and foundation settlement, it has the directive significance for high-speed railway with CFG pile composite foundation.     

A CASE STUDY OF COMPOUND FOUNDATION SUPPORTED BY SAND AND OVAL STONE PILES

This paper describs a case study of foundation engineering for forming sand and oval stone piles through the action of quaking, water striking,pouring and packing by a pile driver. The piles and packking mud are combined, forming a compound foundation to support the upper loads. This paper introduces the design and construction of this engineering. In order to check this method for consolidating the soft foundation,the loading test and the settlement observation in site are made. After the construction work,there has been an organized technical identifying meeting. The result out of the identification is positive.     

Numerical simulation analysis on small clear spacing crossing viaduct pile foundation of shielded subway tunnels

Aimed at the problem of the in partial section of the Nanjing Metro Line 3, the three-dimensional pattern of tunnel, segment and pile foundation was established after appropriate simplification. The simulation results showed that, the Overpass pile foundation of Shield Tunneling to Adjacent Metro Shield Tunnel will have effect on the force and deformation of the earth's surface and pile foundation, the maximum deformation value of the earth's surface is larger than that of the pile foundation top, stress concentration appeared in right working slope lower side segment of tunnel. Through the comparison with field monitoring results, the field dates is consistent with the Numerical Simulation Results, the execution parameters are advised to be well controlled in the further construction, in the same time strengthing the track monitoring, tracking grouting reinforcement should be carried when necessary. The research results could provide reference for the smooth going of the project.     

河南省土地开发整理潜力分区研究

本研究为河南省土地利用总体规划修编、耕地占补平衡目标实现提供前期研究。借助Mapinfo与VBA建立土地开发整理潜力调查数据库,建立潜力测算模型。通过区域权属图库的快速构建、区域地形条件、区域农民收入基础数据库的建立,以及农田整理、村庄整理、土地开发和土地复垦潜力测算,借助GIS实现土地开发整理潜力综合评价,并对土地整理重点区域和重大工程的划分标准进行了分析。笔者研究将河南省划分为十个土地开发整理潜力分区,确定了农田整理、村庄整理、土地开发和土地复垦重点区域,同时确定了河南省五大土地开发整理重大工程。     

Deformation of Soft Ground with Consideration of the Concomitant Damage

On the basis of continuum damage mechanics theory, the effective stress theory of damaged porous media was presented and its modified self contained seepage differential equation was deduced. The traditional Drucker Prager yield criterion subsequently was modified, and a coupled seepage and damage finite element computer program compiled that was combined with the modified Biot consolidation equation. A simple roadbed foundation model then was analyzed and calculated using the computer program we compiled, and the typical node settlement, pore pressure, and damage variables were discussed and compared with those from the analytic solution. The results show that the damage finite element program we compiled is reasonable and effective.     

Study on Effect of Longitudinal Reinforcement Ratio on Shear Behavior of Restrained Beams with Web Reinforcement

In this paper, five restrained beams with web and different longitudinal reinforcement ratio as well as above longitudinal reinforcement truncated were tested under static point loads. On this basis, the overall process of cracking development under shear and the effect of longitudinal reinforcement ratio on shear strength was investigated     

Consideration of External Prestressing Technique Applied to Bridge Reinforcement

The external prestresing technique has become an important method since it was used in the reinforcement of the upper structure of existing bridge. In this paper, the advantages and disadvantages of this method in brief are introduced and emphasis is put on the consideration and progress of its application.     

Settlement Analysis on Building near Retaining Pile of Deep Foundation Pit

The building settlement near a foundation pit project in Yanzhou is calculated by using calculation method related to settlement of the soil near a foundation pit, Comparing and analyzing calculated settlement values with measured settlement ,the reason for the gap between theoretically calculated values and measured settlement values is pointed out, On the foundation of careful research and analysis of the measured building settlement values ,the factors influencing the settlement of building near the foundation pit are summarized. Finally, according to practical measured values and influ- encing factors, how the settlement of building near the foundation pit is influenced was carefully analyzed. A conclusion that has practical role in Engineering is presented,which can serve reasonably for instructing foundation pit retaining design.     

Deformation Monitoring and Its Control in a Shallow buried Large span Tunnel Constructed Using the Pile Beam Arch Method

Deformation monitoring and control measures of a shallow buried large span tunnel constructed using the pile beam arch (PBA) method are described, taking the North Gongti Road Station of Beijing Metro line 10 as an example. Based on the monitoring datum, the crown settlement, convergence, ground settlement of the tunnel and the bridge foundation settlement are analyzed. The results show that (1) the PBA tunneling method can restrain the ground settlement and deformation of a shallow buried large span tunnel; (2) the depth, tunnel span and pilot tunnel construction may influence the deformation of a shallow buried large section tunnel significantly; and, (3) advanced conduit grouting, timely preliminary support and permanent lining construction can reduce the deformation effectively.     

制度约束下的乡村人居环境建设模式研究——以湖南省衡南县工联村为例

优化乡村人居环境,改善农户生活质量,统筹城乡发展是社会主义新农村建设的一项重要内容。以实地调研为基础资料,以湖南省新农村示范点——工联村为例,探索制度约束下乡村人居环境建设的特征、困境与优化路径。在集体合作经营体制下,工联村人居环境建设在筹集资金、约束农户人居行为、改善基础设施、推进社会事业等方面具有一定的制度优势,但也存在诸多困境。从4个方面提出了优化路径,即鼓励制度创新,完善人居环境建设模式;优化村庄布局,规范农户居住行为;加快村庄整治,引导农户生活行为;整体营销村庄,扩大人居环境示范效应。     

Study on Seismic Behavior of Edge Slab-column Connection

Under the action of lateral forces and vertical loads, the connection of reinforced concrete slab-column structure will not only transfer significant shear forces, but also unbalanced moment. As to the edge slab-column connection, even if there is no later force, it will also transfer unbalanced moment due to the asymmetry. Currently, most tests and studies focus on interior connections, but there are few tests or studies on edge slab-column connections. A relatively new type of shear reinforcement named shear-stud reinforcement was applied in edge column-slab connections and study on the seismic behavior of these connections was conducted. Tests and finite element analysis of three full-scale reinforced concrete edge slab-column connections subjected to gravity and unbalanced moment were completed in this paper, and main conclusions were as following: the bearing capacity, deformation capacity and seismic behavior of connections reinforced with shear-stud reinforcement are improved; deformation of specimens reinforced with shear-stud reinforcement could meet requirements of current codes; the performance of energy dissipating is as good as the common connections, and has reached the medium ductility level.