残余强度状态下原状滑带土蠕变特性试验研究

三峡库区许多古滑坡在重力等内、外地质营力作用下呈现出长期而缓慢的变形特征,具有明显的蠕变属性。复活型古滑坡的滑带常处于残余强度状态,其运动特征主要受滑带土力学性质和应力状态控制,研究原状滑带土在残余强度状态下的蠕变特性,对于了解复活型古滑坡滑动机制及预测其运动趋势具有重要意义。针对三峡库区黄土坡滑坡原状滑带土开展环剪试验,研究了不同应力水平条件下滑带土在残余强度状态下的蠕变变形规律。结果表明,滑带土的蠕变速率与剪切应力比R_(CSR)(蠕变剪切应力与残余强度的比值)呈正相关变化,当R_(CSR)接近蠕变阈值1时,滑带土等速蠕变明显,部分试验条件下继而发生加速蠕变,在相同R_(CSR)条件下,土样法向应力越大,其蠕变速率也越大。采用Burger模型对蠕变过程进行模拟,获取了模型的各参数。通过分析滑带土等时蠕变曲线,获得滑带土长期抗剪强度约为0.95倍的残余强度。此外,滑带土蠕变速率受固结时间影响,蠕变速率随固结时间增加而减小,滑带土剪切强度随着固结时间和剪切位移的增加可发生一定程度的恢复。

信号交叉口行人自行车交通强度状态划分研究

混合交通是造成交叉口拥堵和交通事故的重要原因之一.为了便于有效的研究交叉口混合交通信号控制策略及交叉口交通仿真,提出了信号交叉口人行横道绿灯时间行人自行车交通强度状态划分方法.分析了交叉口人行横道绿灯放行的交通特性,定义了人行横道绿灯放行时刻行人自行车聚集群的概念.从信号交叉口人行横道的"时空资源"利用角度,提出了划分人行横道绿灯时间行人自行车交通强度状态概念及必要性,选取了行人自行车绿灯时间通过流率、绿灯时间利用率以及行人自行车绿灯时间的空间占有率三个指标作为强度划分依据,选取K均值聚类为强度状态划分方法,对人行横道绿灯时刻行人自行车交通强度状态划分为三类,分别为低强度、中等强度和高强度.结合北京市平乐园交叉口为例,进行了行人自行车交通强度状态划分.

浅析高性能混凝土强度状态早龄期预测方法

结合应用实例,重点介绍了采用回弹法测得高性能混凝土早龄期强度,借助回归方法建立回归方程确定其28 d强度,从而利用控制图分析判断高性能混凝土强度状态是否稳定的方法。

老龄舰船总纵强度状态评估可行性研究

针对老龄舰船船体结构评估问题,首先引入了中国船级社2011版《现有船状态评估程序指南》;然后,论述了老龄舰船的腐蚀特点及腐蚀程度测定方法,并给出了剩余剖面模数计算方法。再以某舰船为例,依据该指南对其典型舱段总纵强度状态进行了评估;最后,运用ABAQUS有限元软件直接对该舱段的现有状态总纵强度进行了计算并与《现有船状态评估程序指南》得出的总纵强度状态评估结果进行了对比分析。结果表明:该指南对于老龄舰船技术状态评估具有良好的可行性和适用性。

基于直剪试验的土体变形时间效应及状态类别分析

开展了不同剪应力水平下土体剪切位移的时间效应特征分析,提出了随剪应力水平增加,土体变形状态对应呈现快速稳定、缓慢稳定、缓慢破坏和快速破坏4种演化类别。通过粉质黏土蠕变直剪试验,对不同压实度下与剪应力水平相对应的土体剪切位移时间效应的4种状态类别进行了研究。采用幂函数拟合剪切位移时间历程试验数据,将幂次值作为划分变形状态类别的理论判据,基于幂次值与剪应力水平对应关系的曲线形态特征,得到了土体4种变形状态对应的3个剪应力水平阈值,提出了基于Coulomb强度公式表达的相应变形状态强度参数及其与极限状态强度参数的关系式。针对高速铁路无砟轨道路基工后沉降控制须满足毫米级变形的特殊要求,明确了应将土体变形时间效应控制于快速稳定状态作为路堤填料选择及压实标准的设计原则和技术条件。所得成果对构建高速铁路路基土工结构变形状态控制设计技术提供了理论和试验依据。

再论粒状材料强度异向性规律的理论表示式

本文对笔者此前所提出的粒状材料强度异向性规律的理论表示式作了进一步的研究，将它改而表示成不依赖于强度参量tgΨ（ξ）具体假定形式的更一般形式，并提出“强度状态线”的概念，借此对异向性材料破坏时通常只出现一组破裂面这一基本特征进行了更深入的论述。

Development of process energy intensity formula under different state variables

In a production process, the actual energy consumption is greatly affected by the production state. Certain processing operations are classified into six states, including normal production, abnormal production, planned overhaul, unplanned overhaul, transitional period from unplanned overhaul to normal production (referred for short as unplanned transition) and transitional period from planned overhaul to normal production (referred for short as planned transition). The article takes the analysis of relationship between different states of a certain processing operation and corresponding energy consumptions as a startup point to develop a process energy intensity formula with variables of operating rate, yielding rate and operating frequency, etc. This process energy intensity formula can be used to analyze effectively the pattern of impact exerted by different state variables on energy consumption.

Particle breakage and the mobilized drained shear strengths of sand

This paper presents particle breakage and the mobilized drained shear strengths of sand with the purpose of clarifying the influence of particle breakage on the mobilized shear strengths of sand. Several drained triaxial tests were carried out on Silica sand No.5 under 3 MPa confining pressure to produce the pre-crushed sands in simulating the high- pressure shear process on soil to result in particle breakage, and then the pre-crushed sands were re- sheared in series of drained triaxial tests to investigate the mobilized strengths of the pre-crushed sands in detecting the influence of particle breakage. It was found that, by deteriorating strain-stress behavior, particle breakage resulted in change of stress-dilataney behavior in translation and rotation of the relation of the dilatancy factor and the effective principal stress ratio. For a given initial void ratio, particle breakage resulted in impairment of dilatancy behavior of soil to be more contractive in deterioration of the mobilized friction angle and the mobilized dilatancy angle and reduction of void ratio. However, particle breakage resulted in increase of the mobilized basic friction angle especially before failure. In addition, the influence of particle breakage on the mobilized strengths was revealed to be influenced by the shear stress-strain state.

Modified Mohr-Coulomb strength criterion considering rock mass intrinsic material strength factorization

With the increase of mining depth of mineral resources,the rock mass stress state is being more and more complex.The rock mass show different features,namely,with the increase of hydrostatic pressure,rock mass failure mode turns from brittle tension failure to structure ductile failure and its limit strength also increases.The restriction of minimal principal stress on the initiation and development of microcrack and the change of micro-unit stress state by the intermediate principal stress play a decisive role in the increase of rock mass limit strength.Based on the rock mass failure behavior law under complex stress state and the σ2-dependence on the rock mass strength,we proposed a Modified Mohr-Coulomb(M-MC) strength criterion which is smooth and convex.Finally,the M-MC criterion is validated by multiaxial test data of eight kinds of rock mass.We also compared the fitting results with Mohr-Coulomb criterion(MC).It shows that the new criterion fits the test data better than the Mohr-Coulomb criterion.So the M-MC strength criterion well reveals the rock mass bearing behavior and can be widely used in the rock mass strength analysis.The results can provide theoretical foundations for stability analysis and reinforcement design of complex underground engineering.

State Sampling Dependence of Hopfield Network Inference

The fully connected Hopfield network is inferred based on observed magnetizations and pairwise correlations.We present the system in the glassy phase with low temperature and high memory load.We find that the inference error is very sensitive to the form of state sampling.When a single state is sampled to compute magnetizations and correlations,the inference error is almost indistinguishable irrespective of the sampled state.However,the error can be greatly reduced if the data is collected with state transitions.Our result holds for different disorder samples and accounts for the previously observed large fluctuations of inference error at low temperatures.

Cemented backfill technology based on phosphorous gypsum

Physical-chemical properties of phosphorous gypsum, proportion and cemented mechanism of slurry with gypsum as aggregate were studied to remove the harms of gypsum pile, combining with difficult problems of excessive mined-out gobs, enormous ore body under roadway and low recovery ratio of Yongshaba Mine, Kaiyang Phosphor Mine Group, Guizhou Province, China. An appropriate backfill system and craflwork were designed, using shattering milling method to crush gypsum, double-axles mixing and strong activation mixing way to mix slurry, cemented slurry and mullock backfill alternately process. The results show that gypsum is fit for backfilling afterwards by adding fly ash, though it is not an ideal aggregate for fine granule and coagulate retardation. The suggested dosage （the mass ratio of cement to fly ash to gypsum） is 1：1：6-1：1：8 with mass fraction of solid materials 60%-63%. Slurry is transported in suspend state with non-plastic strength, and then in concretion state after backfilling. The application to mine shows the technology is feasible, and gypsum utilization ratio is up to 100%. Transportation and backfill effect is very good for paste-like slurry and drenching cemented slurry into mullock, and the compressive strength and recovery ratio are 2.0 MPa and 82.6%, respectively, with the maximum subsidence of surface only 1.307 mm. Furthermore, the investment of system is about 7 × 10^6 yuan （RMB）, only 1/10 of that of traditional paste backfill system.

IMPROVED SCHEME OF AXISYMMETRIC TYPHOON BOGUS MODEL AND ITS IMPACT ON NUMERICAL SIMULATION OF TYPHOON NOCKTEN (NO.0405)

There is distinct difference in the tangential wind profile between different typhoons in the western North Pacific. At present, only two parameters, maximum wind and radius of maximum wind, are used in NCAR-AFWA bogus for MM5 mesoscale numerical model. As a result, sometimes the outer structure of typhoon cannot be described accurately. The tangential wind profile of NCAR-AFWA bogus is improved by introducing radii of 25.7 m/s and 15.4 m/s, and then the track and intensity of Typhoon Nockten (No.0425) are simulated. The results show that the simulations of track and intensity of typhoon both have been improved by simultaneously introducing the radii in the tangential wind profile of typhoon bogus. At the same time, there is improvement in the gale wind range of the typhoon simulated.

Relationship between wave steepness and wave age in the course of wind wave growth

It is traditionally assumed that the relationship between wave steepness and wave age is inde- pendent of the wind wave growth state. In fact, the traditional relationship can not describe the whole course of wind wave growth. This paper assumes that the relationship between wave steepness and wave age changes with the variety of dimensionless fetch. Based on the relationship proposed by Hou and Wen (1990), a new relation- ship in the course of wind wave growth is revealed. Comparisons between the present study and other previous relationships show that this new relationship explains better the observations than the other existing relationships. In the case of small fetch, wave age value increases more quickly than other models while it is in opposition to that in the case of large fetch. The result in present paper can clearly reflect the whole course of wind wave growth, it is an improvement for traditional results.Key words: wave steepness, wave age, relationship between wave steepness and wave age

Semi-solid near-net shape rheocasting of heat treatable wrought aluminum alloys

Flexibility of the CSIR-RCS, induction stirring with simultaneous air cooling process, in combination with high pressure die casting is successfully demonstrated by semi-solid rheocasting of plates performed on commercial 2024, 6082 and 7075 wrought aluminum alloys. Tensile properties were measured for the above mentioned rheocast wrought aluminum alloys in the T6 condition. The results showed that tensile properties were close to or even in some cases exceeded the minimum specifications. The yield strength and elongation of rheocast 2024-T6 exceeded the minimum requirements of the wrought alloy in the T6 condition but the ultimate tensile strength achieved only 90% of the specification because the Mg content of the starting alloy was below the commercial alloy specification. The strengths of rheocast 6082-T6 exceeded all of the wrought alloy T6 strength targets but the elongation only managed 36% of the required minimum due to porosity, caused by incipient melting during solution heat treatment, and the presence of fine intermetallie needles in the eutectic. The yield strength of rheocast 7075 exceeded the required one and the ultimate tensile strength also managed 97% of the specification; while the elongation only reached 46% of the minimum requirement also due to incipient melting porosity caused during the solution heat treatment process.

受压混凝土灌注桩的桩身材料控制

通过静载荷试验中出现的桩身材料破坏形态分析,以混凝土材料在复合应力状态下桩压强度有所提高为出发点,提出关于桩基设计时桩身材料强度取值的几点建议。

Study on Interfacial Bonding State of Ag-Cu in Cold Pressure Welding

The interfacial bonding of Ag-Cu (they are limited soluble) formed by the technology of cold pressure welding was discussed from the point of metallurgic view in this paper. Meanwhile, tensile test and microscopic test were adopted for studying the state of interfacial bonding, suggesting that the joint of Ag-Cu has not only strong welding joint but also atomic diffusion on the interface. For Ag-Cu, the interaction of dislocation caused by plastic deformation will cause the strain and the vibration of microconstructer defects, accompanied by emitting energy. The energy increases the atomic action and the amplitude of atomic vibration, and the result is that the atom can diffuse to several lattice parameters deep from interface to inner metals. Therefore, under the condition of chemical potential gradient, the special technique, cold pressure welding rather than basic requirements of diffusion should be taken into account. During the cold pressure welding, plastic deformation plays an important role for it causes the metals′ displacement, crystal defects, further activates the surface atoms. Finally, the fracture of atomic bonding leads to the atomic exchange and diffusion between the new metals′ surfaces.In other words the metals Ag,Cu can achieve solidate bonding by cold pressure welding accompanied by the atomic diffusion. Moreover, theoretical analysis and calculation on the basis of thermodynamics, crystallogy, so- lid physics,etc, have been applied to calculate the amount of atomic diffusion, which has further proved the testing results that joint Ag-Cu has strong bonding strength through the mechanism of atomic diffusion.

Wing crack propagation model under high hydraulic pressure in compressive-shear stress state

A new wing crack model subjected to hydraulic pressure and far-field stresses was proposed considering the effect of hydraulic pressure in wing crack and the connected part of the main crack on the stress intensity factor at the wing crack tip. With the equivalent crack length Ieq of the wing crack introduced, the stress intensity factor Kl at the wing crack tip was as- sumed to the sum of two terms： on one hand a component K1^（1） for a single isolated straight wing crack of length 21, and subjected to hydraulic pressure in the wing crack and far-field stresses; on the other hand a component K1（2） due to the effective shear stress induced by the presence of the equivalent main crack. The lateral tensile stress and hydraulic high pressure are the key factors that induce crack propagation unsteadily. The new wing crack theoretical model proposed can supply references for the study on hydraulic fracture in fractured masses, hydraulic fracturing in rock masses.

Nonlinear Interaction and Entanglement Transfer from SU(1,1) Coherent State to Mixed Atoms

For nonlinear interactions with different forms of intensity-dependent coupling, entanglement transfer from the correlated two-mode SU（1,1） coherent states （SCS） to the initially separable and mixed atoms is investigated. It is found that suitable intensity-dependent coupling can enhance the entanglement transfer and make the atomic entanglement evolve periodically especially for the initially mixed atomic states. For SCS, the entanglement between the two modes is strengthened with the increase of the photon number difference （PND） between the two modes of the fields. When PND is odd, the entanglement between the atoms is less than that when PND is even.

形成良好的青少年举重运动员比赛心理过程研究

形成良好的运动员心理状态对运动训练、比赛提高成绩有着重要作用,对青少年举重运动员形成良好比赛心理系统地、综合调查研究的基础上,初步分析了青少年举重运动员赛前、赛中、赛后的心理状态主要表现、心理因素对比赛的影响,及青少年举重运动员心理基础训练研究。

Experimental investigation on strength and deformation of plain high-strength concrete under multiaxial stress state

To investigate the strength and deformation behavior of plain high-strength concrete （HSC） under muhiaxial stress states, a large static-dynamic true triaxial machine was employed, and muhiaxial tests were performed on 100 mm × 100 mm × 100 mm cubes concrete specimens. Friction-reducing pads were three-layer plastic membranes with glycerine in-between for the compressive loading plane. The tensile loading plane of concrete samples was processed by attrition machine, and then the samples were glued up with the loading plate with structural glue. Failure modes of specimens were described. The principal static compressive strengths, strains at the peak stress and stress-strain curves were measured, and the influence of stress ratios on them was analyzed as well. Experimental results show that the ratio of the compressive strength σ3f over the uniaxial compressive strengthfo depends on brittleness-stiffness of concrete besides stress state and stress ratios. The formula of Kupfer-Gerstle＇ s and Ottosen＇ s failure criterion for plain HSC under biaxial compression and muhiaxial stress state is proposed respectively.