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基质吸力 2

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剖宫产瘢痕妊娠 1

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Prediction of hydro-suction dredging depth using data-driven methods

《结构与土木工程前沿（英文）》 2021年第15卷第3期页码 652-664 doi: 10.1007/s11709-021-0719-7

摘要： In this study, data-driven methods (DDMs) including different kinds of group method of data handling (GMDH) hybrid models with particle swarm optimization (PSO) and Henry gas solubility optimization (HGSO) methods, and simple equations methods were applied to simulate the maximum hydro-suction dredging depth (h_s). Sixty-seven experiments were conducted under different hydraulic conditions to measure the h_s. Also, 33 data samples from three previous studies were used. The model input variables consisted of pipeline diameter (d), the distance between the pipe inlet and sediment level (Z), the velocity of flow passing through the pipeline (u₀), the water head (H), and the medium size of particles (D₅₀). Data-driven simulation results indicated that the HGSO algorithm accurately trains the GMDH methods better than the PSO algorithm, whereas the PSO algorithm trained simple simulation equations more precisely. Among all used DDMs, the integrative GMDH-HGSO algorithm provided the highest accuracy (RMSE = 7.086 mm). The results also showed that the integrative GMDHs enhance the accuracy of polynomial GMDHs by ~14.65% (based on the RMSE).

关键词： sedimentation water resources dam engineering machine learning heuristic

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Magnetohydrodynamic slip flow and diffusion of a reactive solute past a permeable flat plate with suction

Krishnendu BHATTACHARYYA, G. C. LAYEK

《化学科学与工程前沿（英文）》 2011年第5卷第4期页码 471-476 doi: 10.1007/s11705-011-1130-z

摘要： The magnetohydrodynamic (MHD) boundary layer slip flow and solute transfer over a porous plate in the presence of a chemical reaction are investigated. The governing equations were transformed into self-similar ordinary differential equations by adopting the similarity transformation technique. Then the numerical solutions are obtained by a shooting technique using the fourth order Runge-Kutta method. The study reveals that due to the increase in the boundary slip, the concentration decreases and the velocity increases. On the other hand, with an increase in the magnetic field and mass suction, both boundary layer thicknesses decreased. As the Schmidt number and the reaction rate parameter increases, the concentration decreases and the mass transfer increases.

关键词： slip flow MHD boundary layer reactive solute diffusion flat plate suction/injection

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heat source/sink on unsteady MHD boundary layer flow and heat transfer over a shrinking sheet with suction

Krishnendu Bhattacharyya

《化学科学与工程前沿（英文）》 2011年第5卷第3期页码 376-384 doi: 10.1007/s11705-011-1121-0

摘要： In this paper, an investigation is made to study the effects of radiation and heat source/sink on the unsteady boundary layer flow and heat transfer past a shrinking sheet with suction/injection. The flow is permeated by an externally applied magnetic field normal to the plane of flow. The self-similar equations corresponding to the velocity and temperature fields are obtained, and then solved numerically by finite difference method using quasilinearization technique. The study reveals that the momentum boundary layer thickness increases with increasing unsteadiness and decreases with magnetic field. The thermal boundary layer thickness decreases with Prandtl number, radiation parameter and heat sink parameter, but it increases with heat source parameter. Moreover, increasing unsteadiness, magnetic field strength, radiation and heat sink strength boost the heat transfer.

关键词： MHD boundary layer unsteady flow heat transfer thermal radiation heat source/sink shrinking sheet suction/injection

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On the MHD squeeze flow between two parallel disks with suction or injection via HAM and HPM

null

《机械工程前沿（英文）》 2014年第9卷第3期页码 270-280 doi: 10.1007/s11465-014-0303-0

摘要：

An analysis has been performed to study the problem of magneto-hydrodynamic (MHD) squeeze flow of an electrically conducting fluid between two infinite, parallel disks. The analytical methods called Homotopy Analysis Method (HAM) and Homotopy Perturbation Method (HPM) have been used to solve nonlinear differential equations. It has been attempted to show the capabilities and wide-range applications of the proposed methods in comparison with a type of numerical analysis as Boundary Value Problem (BVP) in solving this problem. Also, the velocity fields have been computed and shown graphically for various values of physical parameters. The objective of the present work is to investigate the effect of squeeze Reynolds number, Hartmann number and the suction/injection parameter on the velocity field. Furthermore, the results reveal that HAM and HPM are very effective and convenient.

关键词： Homotopy Analysis Method Homotopy Perturbation Method incompressible flow magneto-hydrodynamic flow parallel disks

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Studying the stress-suction coupling in soils using an oedometer equipped with a high capacity tensiometer

Trung Tinh LE, Yu-Jun CUI, Juan Jorge MU?OZ, Pierre DELAGE, Anh Minh TANG, Xiang-Ling LI

《结构与土木工程前沿（英文）》 2011年第5卷第2期页码 160-170 doi: 10.1007/s11709-011-0106-x

摘要： In the context of research into deep nuclear waste disposal, various works have concerned the hydromechanical behavior of Boom clay, a stiff plastic clay extracted in the SCK-CEN Underground Research Laboratory near the Mol City (Belgium), at a depth of 223 m. Due to some amount of smectite minerals in the clay fraction, Boom clay exhibits swelling properties when hydrated under low stresses. To investigate some aspects of the hydromechanical behavior of Boom clay, oedometer compression tests were carried out on samples of Boom clay close to saturation and submitted to an initial suction. During oedometer compression, the changes in suction with increased vertical stress are monitored by means of a high capacity tensiometer installed at the bottom of the sample. Some aspects related to hydromechanical couplings are examined through the investigation of the changes in suction during oedometer compression, a somewhat delicate and poorly documented experimental approach. A comparison is also made with a completely different soil sample under suction, i.e. a statically compacted unsaturated low plasticity silt. Some technical difficulties typical of this new experimental approach are first described in detail so as to optimize the interpretation of the data obtained. The experiment allows the determination of the point at which suction is changed to positive pressure during compression. Below this point, the ratio between the vertical stress and the change in suction are determined. Above this point, the data show that positive pore pressures are dissipated in a common way. The suction/stress behavior during unloading is also described and discussed. Finally, an interpretation in terms of microstructure effects is provided for both samples. The experimental approach initiated here seems to provide interesting further application to better understand hydromechanical couplings in natural soils in relation with suction increase during stress release.

关键词： Oedometer tensiometer swelling physicochemical and mechanical effects stress/suction coupling soil plasticity

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Stability analysis of layered slopes in unsaturated soils

Guangyu DAI; Fei ZHANG; Yuke WANG

《结构与土木工程前沿（英文）》 2022年第16卷第3期页码 378-387 doi: 10.1007/s11709-022-0808-2

摘要： This study presents stability analyses of layered soil slopes in unsaturated conditions and uses a limit equilibrium method to determine the factor of safety involving suction stress of unsaturated soil. One-dimensional steady infiltration and evaporation conditions are considered in the stability analyses. An example of a two-layered slope in clay and silt is selected to verify the used method by comparing with the results of other methods. Parametric analyses are conducted to explore the influences of the matric suction on the stability of layered soil slopes. The obtained results show that larger suction stress provided in unsaturated clay dominates the stability of the layered slopes. Therefore, the location and thickness of the clay layer have significant influences on slope stability. As the water level decreases, the factor of safety reduces and then increases gradually in most cases. Infiltration/evaporation can obviously affect the stability of unsaturated layered slopes, but their influences depend on the soil property and thickness of the lower soil layer.

关键词： slope stability suction stress unsaturated soil layered slope limit equilibrium

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Behavior of materials for earth and rockfill dams: Perspective from unsaturated soil mechanics

Eduardo E. ALONSO, Rafaela CARDOSO,

《结构与土木工程前沿（英文）》 2010年第4卷第1期页码 1-39 doi: 10.1007/s11709-010-0013-6

摘要： The basis of the design of earth and rockfill dams is focused on ensuring the stability of the structure under a set of conditions expected to occur during its life. Combined mechanical and hydraulic conditions must be considered since pore pressures develop during construction, after impoundment and in drawdown. Other instability phenomena caused by transient flow and internal erosion must be considered. The prediction of the hydro-mechanical behavior of traditional and non-traditional materials used in the construction of dams is therefore fundamental. The materials used for dam’s construction cover a wide range from clayey materials to rockfill. In a broad sense they are compacted materials and therefore unsaturated materials. A summary of the current level of knowledge on the behavior of traditional materials used in the construction of dams is presented in the paper. Regular compacted materials (with a significant clay fraction), rockfill and compacted soft rocks are studied with more detail. The latter are non-traditional materials. They are analysed because their use, as well as the use of mixtures of soil and rock, is becoming more necessary for sustainability reasons.

关键词： dams unsaturated soil mechanics suction rockfill clayey soil mixture

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A new method of studying collapsibility of loess

Yuanqing ZHU , Zhenghan CHEN ,

《结构与土木工程前沿（英文）》 2009年第3卷第3期页码 305-311 doi: 10.1007/s11709-009-0040-3

摘要： A new triaxial testing system that could control suction in wetting-induced collapsible tests was successfully developed to study the suction effects on wetting-induced collapsible deformation. The pedestal of the triaxial cell was made up of two parts, and the equipment not only could control suction but also could make water accessible to soil. A pressure/volume-controlled equipment was combined with the triaxial system to measure the water volume absorbed by samples accurately and to add pressure on water to filtrate into the sample. The apparatus could measure volume change precisely and keep the deviator stress unvaried, as well as measure the volume of water filtrating into the samples exactly. A triaxial collapsible testing procedure was described using the new apparatus for undisturbed collapsible loess with controlled suction. Furthermore, a series of double triaxial collapsible tests were conducted under different suctions and the same net cell pressure, and tests under different net cell pressures and the same suction were also done. It was indicated that the collapsible deformation increased with the increasing suction, and the effect of the net cell pressure on collapsible deformation was remarkable. The new triaxial apparatus was a useful facility to study the collapsible behavior of loess.

关键词： triaxial apparatus for collapsible soils controlled suction pressure/volume controlled equipment double triaxial collapsible test single triaxial collapsible test

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Investigation of the hydro-mechanical behaviour of compacted expansive clay

Yujun CUI, An Ninh TA, Anh Minh TANG, Yingfa LU,

《结构与土木工程前沿（英文）》 2010年第4卷第2期页码 154-164 doi: 10.1007/s11709-010-0019-0

摘要： The hydro-mechanical behaviour of compacted expansive Romainville clay was investigated. The soil was air-dried, crushed, and passed through a 2 mm sieve before being statically compacted to a dry density of 1.35 Mg/m. The mechanical behaviour was investigated by tests in oedometer with controlled suction using the vapor equilibrium technique (suction = 0, 9, 39, and 110 MPa). The vertical stress was applied in the range of 0–800 kPa. The experimental results are shown as follows: 1) wetting-induced swelling was higher at lower vertical stresses; 2) the vertical stress under which no swelling occurred during water flooding was estimated at 60 kPa, which can be considered as the swelling pressure of the soil tested; 3) the soil compressibility (changes of volume upon stress increases) was strongly influenced by the soil suction: the lower the suction, the higher the compressibility. The hydraulic behaviour was investigated using a large-scale infiltration chamber (800 mm × 1000 mm in section and 1000 mm high). The large size of the soil column allowed burying the volumetric water content sensors (ThetaProbe) without significantly affecting the water transfer and the soil swelling during infiltration. The soil suction was monitored along the soil height (every 100 mm) using various relative humidity sensors and psychrometers. In the infiltration test, water was kept on the soil surface and changes in suction and volumetric water content were monitored for 338 d. The wetting front has reached the bottom of the soil column at the end of the test. The data from the simultaneous monitoring of suction and water content were used to determine the water retention curve and the unsaturated hydraulic conductivity using the instantaneous profile method. It has been observed that the soil water retention curve depends on the soil depth; that is to be related to the soil depth-dependent swelling. The unsaturated hydraulic conductivity was found to be quite low, comprised between 3 × 10 m/s (at saturated state) and 10 m/s (at about 100 MPa suction).

关键词： Romainville clay suction control oedometer test large infiltration task hydro-mechanical behaviour

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陆上特大型沉井施工技术

邱琼海,林帆,姜江华

《中国工程科学》 2010年第12卷第4期页码 14-20

摘要：

泰州大桥主桥采用主跨2×1 080 m三塔两跨两锚碇悬索桥，其中南、北锚碇基础为特大型沉井，矩形平面尺寸为67.9 m×52.0 m，高度分别为41 m,57 m。针对锚碇基础覆盖层深厚、基础尺寸巨大、沉井下沉深度深等特点，通过施工技术的攻关，顺利完成了砂桩复合地基处理、沉井制作和拼装、钢壳沉井混凝土填充、混凝土沉井接高施工、水力机械冲吸式排水下沉和空气吸泥机吸泥下沉等多项施工工序，为今后陆上特大型沉井施工提供了借鉴。文章简要介绍了南、北锚碇陆上特大型沉井的施工技术。

关键词：悬索桥锚碇沉井拼装深井降水地基沉降空气吸泥桥梁施工

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海上风电场基础形式及配套施工技术

秦顺全,张瑞霞,李军堂

《中国工程科学》 2010年第12卷第11期页码 35-39

摘要：

根据不同的水深及地质条件，结合已建成的海上风电场基础形式及施工方法，介绍和研究了重力式、单桩、群桩、设置沉箱、沉井及吸力式筒形基础等几种形式。对不同的基础形式，分别提出了自升式平台、浅吃水半潜驳、打桩船及整体浮运吊装等相应的基础施工方法。根据风机机组类型，对塔筒和风机的安装也做了介绍。

关键词：海上风电场基础形式桩基础导管架基础吸力式筒形基础设置沉箱风机安装

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非饱和土的塑性体应变与剪应变的相互作用原理

王靖涛

《中国工程科学》 2007年第9卷第11期页码 11-15

摘要：

将岩土塑性体应变与剪应变的相互作用原理拓展到了非饱和土领域。除了塑性体应变与剪应变的相互作用外，在非饱和土中出现了两类新的相互作用，吸力-塑性体应变和孔隙气压力-塑性体应变。吸力具有二重性质，其对塑性体应变作用包括两个相反的方面。基于吸力性质，阐明了非饱和土的一些独特的性质，诸如有效应力参数的物理涵义，吸力对体积变化和前期固结压力的影响和湿陷机理等。另外，应用拓展的塑性体应变与剪应变相互作用原理，从理论上证明了非饱和土的临界状态线是存在的和唯一的，以及它与应力历史无关。

关键词：塑性体应变与剪应变的相互作用原理非饱和土基质吸力有效应力原理

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非饱和土坡危险含水量分析

张士林,王冬梅,李根华

《中国工程科学》 2004年第6卷第5期页码 71-75

摘要：

介绍了由于雨水入渗，使非饱和土坡的含水量发生变化，而含水量正是与基质吸力有着直接的联系；同时通过分析条件水压力和非饱和土的容重与含水量的变化规律，得到基质吸力、饱和度、非饱和土容重与整个土坡的稳定性规律，也就是安全系数与含水量分布的规律。得出当土坡处于危险状况下的含水量分布，即当土坡中的含水量达到危险含水量时，土坡处于危险状态。因此，通过监测土坡的含水量的变化，获得土坡的稳定信息，为生产和安全提供保障。

关键词：非饱和土稳定性分析降雨入渗体积含水量基质吸力

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Enhanced dewatering characteristics of waste activated sludge with Fenton pretreatment: effectiveness and statistical optimization

Guangyin ZHEN, Xueqin LU, Baoying WANG, Youcai ZHAO, Xiaoli CHAI, Dongjie NIU, Tiantao ZHAO

《环境科学与工程前沿（英文）》 2014年第8卷第2期页码 267-276 doi: 10.1007/s11783-013-0530-3

摘要： In this work, the enhanced dewaterabing characteristics of waste activated sludge using Fenton pretreatment was investigated in terms of effectiveness and statistical optimization. Response surface method (RSM) and central composite design (CCD) were applied to evaluate and optimize the effectiveness of important operational parameters, i.e., H O concentrations, Fe concentrations and initial pH values. A significant quadratic polynomial model was obtained ( 0.9189) with capillary suction time (CST) reduction efficiency as the response. Numerical optimization based on desirability function was carried out. The optimum values for H O , Fe , and initial pH were found to be 178 mg·g VSS (volatile suspended solids), 211 mg·g VSS and 3.8, respectively, at which CST reduction efficiency of 98.25% could be achieved. This complied well with those predicted by the established polynomial model. The results indicate that Fenton pretreatment is an effective technique for advanced waste activated sludge dewatering. The enhancement of sludge dewaterability by Fenton’s reagent lies in the migration of sludge bound water due to the disintegration of sludge flocs and microbial cells lysis.

关键词： Fenton pretreatment response surface methodology (RSM) capillary suction time (CST) dewaterabilty molecular weight distribution

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子宫动脉灌注栓塞联合清宫术治疗子宫剖宫产瘢痕妊娠的效果评价

冯颖,李坚,陈素文,李长东,张晓峰,胡乔飞

《中国工程科学》 2014年第16卷第5期页码 4-10

摘要：

为了探讨经子宫动脉甲氨蝶呤灌注+子宫动脉栓塞联合清宫术对剖宫产瘢痕妊娠（CSP）的治疗价值，本文回顾性地分析了2003 年2 月至2013 年4 月首都医科大学附属北京妇产医院收治的140 例CSP患者的临床资料。2003 年2 月至2010 年3 月35 例CSP患者采用甲氨蝶呤全身及局部注射（简称MTX组）联合清宫术治疗。2010 年4 月至2013 年4 月105 例CSP患者采用子宫动脉甲氨蝶呤灌注+子宫动脉栓塞（简称子宫动脉灌注栓塞，UACE组），栓塞术24～72 h 内在超声引导下行超声/宫腔镜/腹腔镜监测下清宫术，分析其临床疗效。比较两组的手术时间、术中出血、血清人绒毛膜促性腺激素（HCG）转阴时间、住院时间和住院费用，并观察远近期副反应。结果表明，140 例CSP的病例中，阴道超声和腹部超声联合检查确诊140例，北京妇产医院首诊108 例病人，误诊3 例。外院转诊32 例中，均被误诊为宫内早孕而行流产术，术中发生大出血，来北京妇产医院确诊为CSP。采用甲氨蝶呤全身及局部注射联合清宫术，33 例患者治疗成功，2 例因过程中出现大出血而行全子宫切除术。105 例患者采用子宫动脉甲氨蝶呤灌注+子宫动脉栓塞联合清宫术治疗，100 例患者治疗顺利，余下3 例患者因清宫过程中再次大出血而行二次介入术，2 例患者因介入术后血清HCG下降不满意，病理回报考虑滋养细胞疾病转至肿瘤科全身化疗。MTX保守治疗组和UACE治疗组的患者年龄、剖宫产次、妊娠时间、孕囊直径及血清β人绒毛膜促性腺激素（β—HCG）之间，差异无统计学意义，但UACE治疗组在清宫术中出血量，血清β—HCG恢复正常的时间及住院时间上，要明显少于MTX保守治疗组，两组差异有统计学意义。综上，早期诊断是成功治疗CSP的关键，阴道超声是CSP的首选确诊方法，经子宫动脉化疗栓塞联合清宫术治疗瘢痕妊娠是目前安全、快速、防止大出血的有效方法。

关键词：剖宫产瘢痕妊娠子宫动脉栓塞术甲氨蝶呤清宫术