刷方减重下隧道-滑坡平行体系变形演化试验研究

刷方减重工艺在大型复杂滑坡治理中发挥越来越重要的角色。通过室外模型试验,以加载诱发滑坡滑动变形,造成对隧道的破坏影响,以减载的方式模拟刷方减载工艺对隧道的受力变形影响进行研究。结果表明:(1)隧道-滑坡平行体系单滑面情况下滑坡推力在滑体内产生应力效应有一个时间传递变化的过程,即时间效应;(2)滑坡推力对隧道作用沿纵向变形差异大,初步的试验反映出拉压过渡段的位置与滑坡推力的大小相关,滑带位置附近的土体最先达到应力幅值,引起隧道的拉压变形过渡,距离滑带较远位置滑体逐渐达应力幅值过渡;(3)隧道横断面环向应力都是拱顶应力较拱底应力大;(4)隧道环向断面应力呈对称分布,隧道底部受压侧,顶部为受拉侧,底部应变量级小于拱顶,且隧道的变形是不可恢复的;(5)刷方减荷在不同工况下对抑制滑坡变形有不同程度的效用,使隧道应变减小,尤其是滑带附近效果更加显著,这都印证了刷方减重对隧道-滑坡治理的突出效果。

白河三中滑坡灾害治理方案对比分析

以白河三中滑坡治理为实例,提出了两种对比治理方案,方案一是以抗滑桩为主,方案二是以刷方为主。通过对各项施工技术、经济及环境影响等方面的对比分析,结果表明,方案一在该工程治理中施工更加简便,对当地的环境影响较小,更为经济合理。

狮子山滑坡灾害治理方案的对比分析

以白河县狮子山滑坡治理工程为例，提出了两种对比治理方案，方案一是以抗滑桩加挡墙为主，方案二是以刷方加挡墙为主。通过对两种方案的经济性、施工技术及环境影响等方面的对比分析，结果表明，方案一的安全性能和治理效果都具有较大的优越性，对当地的环境影响较小，因而将方案一作为优先推荐方案。

某山区机场高填方滑坡变形特征分析

西南山区某机场高填方边坡在雨季结束后不久产生了变形。通过现场调查,坡体后部土面区出现了三条拉张裂缝,左右侧界也有明显变形迹象,坡脚五级马道水沟挤压变形严重,坡脚挡墙产生一小段垮塌变形。通过地表宏观变形判断坡体处于挤压变形阶段。对此段填方体滑坡及时实施了应急变形监测与工程地质勘察。通过地表变形监测曲线分析,由于错过了初始变形阶段的监测,该滑坡变形一开始就处于等速变形阶段。该滑坡在抗滑桩开挖过程中,变形明显加剧。坡体变形进入加速阶段后,变形速率及变形加速度较等速变形阶段成倍增加。在变形进入临界状态前,及时实施了坡体后部刷方减载,坡脚堆载反压的应急治理措施。应急治理措施实施后,坡体变形速率迅速减小,为永久治理工程的实施争取了时间。

某客运专线DK1622滑坡病害整治方案浅析

介绍了某客运专线DK1622路堑边坡大型滑坡病害产生的原因及特征,重点分析了各种病害整治方案的利弊和整治措施的选择。最终确定采用"大减载+抗滑桩"方案。

滑坡路段锚索固坡方案设计研究

文章以梧柳高速公路某路段滑坡事件为例,分析了其滑坡成因,并综合对比了不同固坡方案的优劣,选定了最佳固坡方案。

711矿山体滑坡群的成因及治理措施

通过对发生在711矿山体上的滑坡群的勘探及降雨和堆石的调查情况,结合对边坡角的演化、渗入坡体水的软化作用等因素的分析,阐明了该滑坡群发生的主要原因。最后对滑坡群提出了刷方减重、埋设抗滑桩等治理方案。

太长高速公路范家岭滑坡特征及成因研究

在野外勘查的基础上,阐述了范家岭滑坡的地质环境条件和滑坡特征,对滑坡的成因进行了分析研究,基于分析研究结果,指出范家岭滑坡的发生与岩性、地形地貌、地质构造、地震、降雨和人类活动有关,现状条件下该滑坡的稳定性总体上较差,建议对滑坡采取地表排水、刷方减载和抗滑桩工程进行治理。该研究成果可为范家岭滑坡的防治提供依据。

邵光高速公路某滑坡成因分析及治理工程设计

邵光高速公路K28+540滑坡为土质滑坡,滑坡体主要成分为残坡积砂质粘性土及花岗岩风化层,边坡沿着土岩交界面发生滑动破坏。通过分析其破坏特征及破坏模式,提出了坡体中上部刷方卸载结合设置锚固工程的治理措施,为类似滑坡的处治提供借鉴。

靖永高速公路土楼互通B匝道滑坡成因分析及工程治理措施

高速公路互通一般选择位于城镇附近,地形上多位于丘陵、低山与平缓地带接触带,山体地形相对较平缓,然而互通区匝道曲线半径较小,难免会对山体坡脚进行切割,为边坡滑坡地质灾害等埋下安全隐患。该文以靖永高速公路土楼互通B匝道右侧高边坡为例,在工程地质的基础上,阐述了滑坡的变形特征、性质,并探讨了边坡滑坡病害的成因,通过分析认为边坡的临空面大小、山体地貌特征及地下水等对边坡变形起到重要的影响作用,针对该边坡的病害特征,对该边坡病害的整治采取刷方卸载、锚固工程及排水工程等相结合的工程措施,通过后期的深孔监测资料,滑坡治理后稳定性较好。

龙岩市快速通道边坡滑坡病害成因分析及工程整治对策

在分析龙岩市城区至高新园区城际快速通道工程K13+770~K14+140段右侧高边坡滑坡工程地质概况的基础上,阐述了滑坡的变形特征、性质,并探讨了滑坡的成因。分析认为边坡的临空面大小及地下水对基岩顺倾边坡演变为滑坡起到重要的作用,针对该滑坡的病害特征,对该滑坡的整治采取刷方卸载、锚固工程强腰、挡墙支挡固脚以及排水工程相结合的工程措施,结合必要的锚索张拉质量检测及抗拔力检测证明锚固工程满足设计及规范要求,通过后期的深孔监测,滑坡趋于稳定。期望对类似的基岩顺倾滑坡整治具有借鉴意义。

EFFECTIVE DOUBLE LOOP CONTROL FOR A SQUARE WAVE BRUSHLESS DC MOTOR

A new type of brushless DC motor has been developed by using a square wave rare earth permanent magnet synchronous motor with its double loop control circuit. The double loop control scheme of the drive system yields a combination of desired characteristics including simplified control structure, small ripple torque, high speed accuracy, wide operating speed range, and fast dynamic response. Experimental results confirm excellent characteristics of the motor.

CFD prediction of local scour hole around bridge piers

In order to predict the local scour hole and its evaluation around a cylindrical bridge pier, the computational fluid dynamics （CFD） and theories of sediment movement and transport were employed to carry out numerical simulations. In the numerical method, the time-averaged Reynolds Navier-Stokes equations and the standard k-e model were first used to simulate the three-dimensional flow field around a bridge pier fixed on river bed. The transient shear stress on river bed was treated as a crucial hydrodynamic mechanism when handling sediment incipience and transport. Then, river-bed volumetric sediment transport was calculated, followed by the modification of the river bed altitude and configuration. Boundary adaptive mesh technique was employed to modify the grid system with changed river-bed boundary. The evolution of local scour around a cylindrical bridge pier was presented. The numerical results represent the flow pattern and mechanism during the pier scouring, with a good prediction of the maximum scour hole depth compared with test results.

A case of colohepatic penetration by a swallowed toothbrush

Although foreign body ingestion is relatively common,toothbrush swallowing is rare. We report a case of a swallowed toothbrush which passed through the ileocecal valve and perforated the proximal transverse colon,then the liver. To our knowledge, this is the first case to be reported,

A High-Accuracy Technique for Re-outputting Scratched Paintings

A method of restoring scratches on old paintings is proposed,and the corresponding high-accuracy output workflow is also developed.Firstly the scanner is selected as an input device to get the RGB(red,green,blue)image of the painting,and for the purpose of capturing high-quality image,scanner characterization is done by using neural network.And then the scratches on the RGB image are restored with the technology of digital inpainting,while the inpainting algorithm is mainly based on gradient vector and fast marching method.Finally the restored image is output with a printer,which is calibrated by using the high order polynomial regression method.In experiment the new replicated painting is well restored in the scratched areas,as well as keeps high resemblance with the original painting.

Quantifying Environmental Sustainability of Buildings through Its Carbon Foot-Print： An Analytical Approach

It is known that the building sector consumes about 40% of earth＇s resources in their process of commissioning, erection and subsequent operation. As a consequence there is significant amount of CO2 emission to the atmosphere. Assessment of environmental performances of buildings has assumed immense significance in such backdrop and calls for assessing the ＂Carbon Footprint＂ of building systems for estimating their environmental compatibility. The present paper discusses a case specific environmental evaluation exercise by estimating the Carbon Footprint of a conventionally constructed tourist accommodation by tracking its resource consumption pattern during both the execution and operational phases in the hot and humid climatic zone of Indian sea-side. The result of the analysis is compared against the average carrying capacity of Earth to develop a method of measuring and quantifying the building＇s environmental performance with respect to Earth＇s reported threshold of tolerance and check the extent of failure or success, as the case may be. This process also leads to a tool named ＇Sustainability Quotient＇. The method of quantification is simple and can be adopted for environmental assessment of both new and old buildings.

Recovering metals from printed circuit board scrap by a mechanical separation process

A mechanical separation process was developed for recovering metals from printed circuit board(PCB) scrap;it included three steps:impact crushing,sieving and fluidization separation.The mechanism of the technique was based on the difference in the crushabilities of metallic and nonmetallic materials in the PCBs that led to the concentrated distribution of metals in particles of larger sizes and nonmetals mostly in particles of smaller sizes.It was found that crushed PCB particles from 0.125 mm to 1.000 mm contained about 80% of metals in the PCBs.Metals acquired satisfactory liberation in particles smaller than 0.800 mm.The crushed PCB particles were sieved into fractions of different size ranges.Each fraction separately went through a gas-solid fluidized bed operating at a selected optimal gas velocity for the specific size range.Approximately 95% of metals in printed circuit board particles from 0.125 mm to 0.800 mm was recovered by the gas-fluidized bed separator at the selected optimal gas velocity.However,separation of metals from particles smaller than 0.125 mm was not satisfactory.Further study is needed on metal recovery from fine particles.

Analysis of passenger boarding time difference between adults and seniors based on smart card data

As an essential component of bus dwelling time, passenger boarding time has a significant impact on bus running reliability and service quality. In order to understand the passengers’ boarding process and mitigate passenger boarding time, a regression analysis framework is proposed to capture the difference and influential factors of boarding time for adult and elderly passengers based on smart card data from Changzhou. Boarding gap, the time difference between two consecutive smart card tapping records, is calculated to approximate passenger boarding time. Analysis of variance is applied to identify whether the difference in boarding time between adults and seniors is statistically significant. The multivariate regression modeling approach is implemented to analyze the influences of passenger types, marginal effects of each additional boarding passenger and bus floor types on the total boarding time at each stop. Results show that a constant difference exists in boarding time between adults and seniors even without considering the specific bus characteristics. The average passenger boarding time decreases when the number of passenger increases. The existence of two entrance steps delays the boarding process, especially for elderly passengers.

The influence of upstream slope on the local scour at drop structure

The drop structure will fail as a result of local scoring downstream.This paper discusses the influence of a drop structures' upstream slope to local scour.Empirical equations of the scour hole were developed by laboratory experiment,theoretical assumptions,and regression analysis.These equations include the maximum scour depth and length during the scouring period,the maximum equilibrium scour depth and length,and the unit width scour rate.The four channel slopes(0%,2%,4%,and 6%) before the drop structure has been included in the analysis.A series of laboratory experiments were conducted to obtain 48 groups of experiments and 419 scour hole profiles during the scouring period.The material used in the scour section is uniform non-cohesive and with a median diameter of d50 = 0.5 mm.The results have been used to develop empirical equations via regression analysis to determine the coefficients of theoretical equations.The high correlation coefficient indicates that the equations developed in this study are suitable for verifying the characteristics of a scour hole at drop structure in the sloped channel.The semi-empirical equation is more accurate than the empirical equation.Compared to a horizontal channel,a sloped channel tends to cause a greater equilibriummaximum scour length,shorter equilibrium maximum scour depth,and faster unit-wide scour rate.

Steady-State Performance Analysis of Brushless DC Propulsion Motor

The brushless DC motor can be used in the marine electric propulsion system for its excellent control characteristics and large thrust. In order to estimate the operating performances of the brushless DC motor for the high-power shipping during the design stage, the steady-state analysis is as important as the dynamic analysis generally. A mathematical model of the brushless DC propulsion motor is established according to the state-space method for the dynamic and steady-state performance analysis. The state-space mathematical model is a set of linear differential equations, so the steady-state currents of the armature windings can be gained directly by the symmetrical boundary conditions and the eigenvalues of the system matrix. The steady-state simulation results are compared with the dynamic ones to validate the correctness of this eigenvector method.