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Investigation of the seismic behavior of grouted sandy gravel foundations using shaking table tests

Tiancheng WANG; Yu LIANG; Xiaoyong ZHANG; Zhihuan RUAN; Guoxiong MEI

《结构与土木工程前沿（英文）》 2022年 第16卷 第9期   页码 1196-1211 doi: 10.1007/s11709-022-0865-6

摘要： Sandy gravel foundations exhibit non-linear dynamic behavior when subjected to strong ground motions, which can have amplification effects on superstructures and can reveal insufficient lateral resistance of foundations. Grouting methods can be used to improve the seismic performance of natural sandy gravel foundations. The strength and stiffness of grouted sandy gravel foundations are different from those of natural foundations, which have unknown earthquake resistance. Few studies have investigated the seismic behavior of sandy gravel foundations before and after grouting. In this study, two shaking table tests were performed to evaluate the effect of grouting reinforcement on seismic performance. The natural frequency, acceleration amplification effect, lateral displacement, and vertical settlement of the non-grouted and grouted sandy gravel foundations were measured and compared. Additionally, the dynamic stress-strain relationships of the two foundations were obtained by a linear inversion method to evaluate the seismic energy dissipation. The test results indicated that the acceleration amplification, lateral displacement amplitude, and vertical settlement of the grouted sandy gravel foundation were lower than that of the non-grouted foundation under low-intensity earthquakes. However, a contrasting result was observed under high-intensity earthquakes. This demonstrated that different grouting reinforcement strategies are required for different sandy gravel foundations. In addition, the dynamic stress-strain relationship of the two foundations exhibited two different energy dissipation mechanisms. The results provide insights relating to the development of foundations for relevant engineering sites and to the dynamic behavior of grouted foundations prior to investigating soil-structure interaction problems.

关键词： sandy gravel foundation     grouting-treated reinforcement     shaking table test     seismic behavior    

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厦门翔安海底隧道F1风化深槽注浆加固技术

郭小红,王梦恕

《中国工程科学》 2011年 第13卷 第9期   页码 38-41

摘要：

以厦门翔安海底隧道涌水量最大、施工难度最大的海域段F1风化槽为研究对象，根据其围岩地质条件和突涌水特点，采用全断面注浆加固和堵水，注浆加固范围为掌子面内及隧道开挖轮廓线外5 m，隧道纵向加固长度为70 m，注浆材料以超细水泥单液浆为主的注浆加固方案。施工期现场监控量测与数值计算结果表明：F1风化深槽围岩注浆加固效果均较为理想，未发生涌水突泥，达到了设计的技术要求。该项研究成果为今后开展类似工程的注浆加固提供了技术借鉴。

关键词： 海底隧道     注浆加固     稳定性     数值仿真    

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Effect of loading rate on shear strength parameters of mechanically and biologically treated waste

《环境科学与工程前沿（英文）》 2022年 第16卷 第12期 doi: 10.1007/s11783-022-1595-7

摘要：

● Mechanical behavior of MBT waste affected by loading rate was investigated.

关键词： Mechanically and biologically treated waste     Landfill     Triaxial test     Loading rate     Axial strain     Shear strength parameter    

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Experimental study on pile-end post-grouting piles for super-large bridge pile foundations

Weiming GONG, Guoliang DAI, Haowen ZHANG

《结构与土木工程前沿（英文）》 2009年 第3卷 第2期   页码 228-233 doi: 10.1007/s11709-009-0019-0

摘要： The application of pile-end post-grouting piles for super-large bridge pile foundations in some important projects was introduced in this paper. There are totally 21 test piles. The maximum pile diameter varies from 2.5 m to 3 m, and the maximum length is 125 m; the bearing capacity of the post-grouting piles is over ten thousands tons. Based on the test results, the bearing capacity, displacement, and bearing characteristic before and after grouting were analyzed. The results show that the bearing capacity of the piles are increased in different degrees after grouting although the technical parameters, including the patterns of grouting pipes, pressure, dosages of cement, duration of grouting lasting time, are different. However, the obtained values are very discrete. In addition, the calculation formula for the post-grouting piles under specified grouting condition was deduced based on the statistics analysis results of 57 test piles. The research results have been applied in the design of bridge foundation.

关键词： self-balanced testing technique     pile-end post-grouting     bearing capacity     grouting technology    

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Seismic performance of fabricated continuous girder bridge with grouting sleeve-prestressed tendon composite

《结构与土木工程前沿（英文）》   页码 827-854 doi: 10.1007/s11709-023-0954-1

摘要： The seismic performance of a fully fabricated bridge is a key factor limiting its application. In this study, a fiber element model of a fabricated concrete pier with grouting sleeve-prestressed tendon composite connections was built and verified. A numerical analysis of three types of continuous girder bridges was conducted with different piers: a cast-in-place reinforced concrete pier, a grouting sleeve-fabricated pier, and a grouting sleeve-prestressed tendon composite fabricated pier. Furthermore, the seismic performance of the composite fabricated pier was investigated. The results show that the OpenSees fiber element model can successfully simulate the hysteresis behavior and failure mode of the grouted sleeve-fabricated pier. Under traditional non-near-fault ground motions, the pier top displacements of the grouting sleeve-fabricated pier and the composite fabricated pier were less than those of the cast-in-place reinforced concrete pier. The composite fabricated pier had a good self-centering capability. In addition, the plastic hinge zones of the grouting sleeve-fabricated pier and the composite fabricated pier shifted to the joint seam and upper edge of the grouting sleeve, respectively. The composite fabricated pier with optimal design parameters has good seismic performance and can be applied in high-intensity seismic areas; however, the influence of pile-soil interaction on its seismic performance should not be ignored.

关键词： seismic performance     continuous girder bridge     grouting sleeve-prestressed tendon composite connections     grouted sleeve connection     design parameters    

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Characterization of humic substances in bio-treated municipal solid waste landfill leachate

Guangxia QI, Dongbei YUE, Yongfeng NIE

《环境科学与工程前沿（英文）》 2012年 第6卷 第5期   页码 711-716 doi: 10.1007/s11783-012-0421-z

摘要： Considerable organic matter remains in municipal solid waste landfill leachate after biological treatments. Humic substances (HSs) dominate the organic matter in bio-treated landfill leachate. In this study, the HSs from landfill leachate treated by membrane bioreactor (MBR-HSs) were analyzed via elemental analysis, ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, and charge polarized magic-angle spinning- C-nuclear magnetic resonance. The characteristic absorption in the UV wavelength range indicated the presence of high C=C and C=O double bonds within the MBR-HSs. Compared with commercial HSs, MBR-HSs had lower carbon content [48.14% for fulvic acids (FA) and 49.52% for humic acids (HA)], higher nitrogen content (4.31% for FA and 6.16% for HA), lower aromatic structure content, and higher carbohydrate and carboxylic atoms of carbon content. FA predominantly had an aliphatic structure, and HA had less condensed or substituted aromatic ring structures than natural HA. The aromatic carbon content of MBR-HSs was lower than that of humus-derived HSs but higher than that of waste-derived HSs, indicating that MBR-HSs appeared to be more similar to humus-derived HSs than waste-derived HA.

关键词： bio-treated landfill leachate     humic substances     elemental analysis     spectroscopic characteristics    

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A new automatic convolutional neural network based on deep reinforcement learning for fault diagnosis

《机械工程前沿（英文）》 2022年 第17卷 第2期 doi: 10.1007/s11465-022-0673-7

摘要： Convolutional neural network (CNN) has achieved remarkable applications in fault diagnosis. However, the tuning aiming at obtaining the well-trained CNN model is mainly manual search. Tuning requires considerable experiences on the knowledge on CNN training and fault diagnosis, and is always time consuming and labor intensive, making the automatic hyper parameter optimization (HPO) of CNN models essential. To solve this problem, this paper proposes a novel automatic CNN (ACNN) for fault diagnosis, which can automatically tune its three key hyper parameters, namely, learning rate, batch size, and L2-regulation. First, a new deep reinforcement learning (DRL) is developed, and it constructs an agent aiming at controlling these three hyper parameters along with the training of CNN models online. Second, a new structure of DRL is designed by combining deep deterministic policy gradient and long short-term memory, which takes the training loss of CNN models as its input and can output the adjustment on these three hyper parameters. Third, a new training method for ACNN is designed to enhance its stability. Two famous bearing datasets are selected to evaluate the performance of ACNN. It is compared with four commonly used HPO methods, namely, random search, Bayesian optimization, tree Parzen estimator, and sequential model-based algorithm configuration. ACNN is also compared with other published machine learning (ML) and deep learning (DL) methods. The results show that ACNN outperforms these HPO and ML/DL methods, validating its potential in fault diagnosis.

关键词： deep reinforcement learning     hyper parameter optimization     convolutional neural network     fault diagnosis    

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84-month observational study of the changes in CD4 T-lymphocyte cell count of 110 HIV/AIDS patients treated

null

《医学前沿（英文）》 2014年 第8卷 第3期   页码 362-367 doi: 10.1007/s11684-014-0363-x

摘要：

This study aimed to evaluate the therapeutic effect of traditional Chinese medicine (TCM) by observing the changes in CD4 T-lymphocyte cell count of 110 cases with human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) treated continuously with TCM for 84 months. Information of 110 HIV/AIDS patients from 19 provinces and cities treated with TCM from 2004 to 2013 was collected. Changes in the indexes of CD4 counts (≤200, 201–350, 351–500 and>500 cells/mm3) at five time points (0, 12, 36, 60 and 84 months) and different treatments [TCM and TCM plus antiretroviral therapy (ART)] were compared. Repeated measures test indicated no interaction between group and time (P>0.05). Degrees of increasing and decreasing CD4 count of the two groups at four different frames were statistically significant compared with the baseline. The CD4 count between the two groups was not statistically significant. For CD4 count of≤200 cells/mm3, the mean CD4 count changes were 21 and 28 cells/mm3 per year for the TCM group and TCM plus ART group, respectively. For CD4 count of 201–350 cells/mm3, the mean CD4 count changes were 6 and 25 cells/mm3 per year for the TCM group and TCM plus ART group, respectively. For CD4 count of 351–500 cells/mm3, the mean CD4 count changes were -13 and -7 cells/mm3 per year for the TCM group and TCM plus ART group, respectively. For CD4 count of>500 cells/mm3, the mean CD4 count changes were -34 and -17 cells/mm3 per year for the TCM group and TCM plus ART group, respectively. Long-term use of TCM could maintain or slow the pace of declining CD4 counts in patients with HIV/AIDS, and may achieve lasting effectiveness.

关键词： AIDS     HIV     CD4     traditional Chinese medicine     linear models    

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Evolution of composite fouling on a vertical stainless steel surface caused by treated sewage

Cheng ZAN, Lin SHI, Xiujuan MA, Wenyan YANG,

《能源前沿（英文）》 2010年 第4卷 第2期   页码 171-180 doi: 10.1007/s11708-009-0068-z

摘要： Composite biological and inorganic fouling occurs in plate heat exchangers (PHEs) using treated sewage as heat transfer medium, which lowers the heat transfer coefficient and increases the frictional resistance. In order to optimize the heat exchange process and improve the anti-fouling strategies, the dynamic behavior of composite fouling at a vertical surface of stainless steel (ANSI 316L) was investigated under typical conditions of PHEs. The growth curves of composite fouling were obtained. The evolution of composite fouling was characterized by means of environmental scanning electron microscopy (ESEM). Backscattered Electron Image (BEI) and energy dispersive X-ray spectrometry (EDS) were used as aids in interpreting the results. The experimental results show that a preliminary stage of a 6-day period with a low fouling growth rate exists during the composite fouling development. A significant change of the fouling growth rate happens after the preliminary stage during which the bacterial behaviors at the surface could be recorded clearly. After the preliminary stage, a space net-shape, mainly consisting of bacteria, extracellular products (EPS) and inorganic particles, could be established on the surface of the fouling layer. The change of fouling growth rate occurs synchronously with the evolution.

关键词： treated sewage     plate heat exchanger     stainless steel     composite fouling     biofouling    

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高压富水断层“外堵内固注浆法”设计新理念与工程实践

张民庆,张梅

《中国工程科学》 2009年 第11卷 第12期   页码 26-34

摘要：

宜万铁路齐岳山隧道F11断层由断层角砾岩、破裂岩、断层泥组成，断层内富含高压水，超前探孔单孔最大涌水量1 800 m3/h，水压力2.5 MPa。针对F11高压富水断层，前期按“以堵为主、限量排放”施工原则，采取全断面帷幕注浆措施，注浆工程量大、进度慢。为及早攻克F11高压富水断层，建设单位多次邀请院士、专家现场踏勘、研讨，提出“注浆加固、分水降压、快挖快封、加强监测、综合治理”施工技术方案，将全断面帷幕注浆调整为外堵内固注浆。对于高压富水断层，通常的设计是加固圈厚一些、加固体强一些，而外堵内固注浆是将隧道周边岩体、水量及水压力分布假定为不均匀性，从而通过超前探孔锁定弱水区和强水区，针对弱水区采取基本注浆，对强水区采取加强注浆，注浆机理为“封堵裂隙、减少水量；固结围岩、改良地层。”注浆时，先通过区域定位孔进行无约束注浆堵水，从而使地层中水量得到有效控制，然后按“合理步距、封堵水流，由外到内、环环相扣，间隔跳孔、锁定水源，增加补孔、区域加强”的注浆理念进行注浆施工。通过现场实践，外堵内固注浆能达到注浆堵水和加固效果。外堵内固注浆与全断面帷幕注浆相比，注浆孔数量和注浆量减少50 %，在水量大时，注浆进度提高80 %，一般情况下提高50 %以上，因此，外堵内固注浆具有广阔的推广应用价值。

关键词： 高压富水断层     不均匀性     注浆堵水加固     外堵内固注浆     创新    

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Improved local control without elective nodal radiotherapy in patients with unresectable NSCLC treated

YANG Kunyu, LIU Li, ZHANG Tao, WU Gang, CAO Fengjun, WANG Jianhua

《医学前沿（英文）》 2007年 第1卷 第4期   页码 381-385 doi: 10.1007/s11684-007-0074-7

摘要： To investigate the influence of prophylactic elective nodal irradiation on the therapeutic results of definitive radiotherapy for patients with stage IIIA or stage IIIB unresectable non-small-cell lung cancer, 55 patients with clinically inoperable advanced non-small-cell lung cancer were studied. After four cycles of induction chemotherapy, the patients were divided into two groups at random. In one group, the elective nodal irradiation was included in clinical tumor volume (CTV) of definitive radiotherapy (ENI group); and in the other group, elective nodal irradiation was not included in CTV (non-ENI group). For the patients in the ENI group, the mean prescription dose for gross tumor volumes was 58.4 Gy, while for the patients in the non-ENI group, it was 65.8 Gy (<0.05). The responsive rates were 45.8% and 74.0% (<0.05), and the rate of the elective nodal failure (ENF) was 4.2% and 11.1%, respectively. Kaplan-Meier analysis showed that the mean local-progression-free survival time was 11.0 and 15.0 months, and one-year local-failure rates were 51.9% and 24.5% (<0.05). The median overall survival time was 13.0 and 15.0 months, respectively ( = 0.084). The one-year survival rates were 55.7% and 72.5%, and two-year survival rates were 0% and 19.9%. There was no significant difference in the occurrences of radiation-associated complications between the two groups. Our results showed that omitting elective nodal irradiation did not result in a high incidence of elective nodal failure. On the contrary, it decreased local failure by increasing prescription doses to the primary diseases and lymphadenopaphy, and thereby it may further prolong the patients survival.

关键词： significant difference     irradiation     unresectable non-small-cell     induction chemotherapy     influence    

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三峡升船机齿条及螺母柱间隙灌浆工艺试验

詹剑霞,李纪虎

《中国工程科学》 2013年 第15卷 第9期   页码 45-49

摘要：

为了选择出合适的灌浆材料和灌浆工艺并模拟升船机齿条、螺母柱间隙灌浆的实际情况，分别进行了灌浆工艺试验与原型灌浆试验。灌浆工艺试验对比了3种国产灌浆材料和德国PAGEL灌浆材料，试验结果表明德国PAGEL灌浆材料物理性能指标和力学性能指标优于国产灌浆材料。在原型灌浆试验中，对灌浆设备选型、搅拌时间、模板密封、灌浆方式、灌浆流速参数控制等方面进行了试验研究，优选出适用于三峡升船机齿条、螺母柱接缝灌浆的材料和合适的灌浆工艺。以上试验效果明显，解决了灌浆密封难度大、易堵管等施工难题。

关键词： 齿条     螺母柱     灌浆     升船机     三峡工程    

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Quantitatively assessing the pre-grouting effect on the stability of tunnels excavated in fault

Xiao YAN, Zizheng SUN, Shucai LI, Rentai LIU, Qingsong ZHANG, Yiming ZHANG

《结构与土木工程前沿（英文）》 2019年 第13卷 第6期   页码 1393-1404 doi: 10.1007/s11709-019-0563-1

摘要： Pre-grouting is a popular ground treatment strategy utilized to enhance the strength and stability of strata during the excavation of a tunnel through a fault zone. Two important questions need to be answered during such an excavation. First, how should the grouting size be determined? Second, when should excavation begin after grouting? These two questions are conventionally addressed through empirical experience and standard criteria because a reliable quantitative approach, which would be preferable, has not yet been developed. To address these questions, we apply a recently proposed numerical approach known as discontinuity layout optimization, an efficient node-based upper bound limit analysis method. A case study is provided utilizing a tunnel located in a stratum characterized by complicated geological conditions, including soft soil and a fault zone. The factor of safety is used to quantitatively assess the stability of the tunnel section. The influences of the grouted zone thickness and the time-dependent material properties of the grouted zone on the stability of the tunnel section are evaluated, thereby assisting designers by quantitatively assessing the effects of pre-grouting.

关键词： pre-grouting     stability analysis     factor of safety     discontinuity layout optimization    

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Analysis of cement-treated clay behavior by micromechanical approach

Dong-Mei ZHANG, Zhen-Yu YIN, Pierre-Yves HICHER, Hong-Wei HUANG

《结构与土木工程前沿（英文）》 2013年 第7卷 第2期   页码 137-153 doi: 10.1007/s11709-013-0204-z

摘要： Experimental results show the significant influence of cement content on the mechanical properties of cement-treated clays. Cementation is produced by mixing a certain amount of cement with the saturated clay. The purpose of this paper is to model the cementation effect on the mechanical behavior of cement-treated clay. A micromechanical stress-strain model is developed considering explicitly the cementation at inter-cluster contacts. The inter-cluster bonding and debonding during mechanical loading are introduced in two ways: an additional cohesion in the shear sliding and a higher yield stress in normal compression. The model is used to simulate isotropic compression and undrained triaxial tests under various confining stresses on cement-treated Ariake clay and Singapore clay with various cement contents. The applicability of the present model is evaluated through comparisons between numerical and experimental results. The evolution of local stresses and local strains in inter-cluster planes are discussed in order to explain the induced anisotropy due to debonding at contact level under the applied loads. The numerical simulations demonstrate that the proposed micromechanical approach is well adapted for taking into account the main physical properties of cement-treated clay, including damage and induced anisotropy under mechanical loading.

关键词： microstructure     cementation     clay     micromechanics     anisotropy     debonding    

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Punching of reinforced concrete slab without shear reinforcement: Standard models and new proposal

Luisa PANI, Flavio STOCHINO

《结构与土木工程前沿（英文）》 2020年 第14卷 第5期   页码 1196-1214 doi: 10.1007/s11709-020-0662-z

摘要： Reinforced concrete (RC) slabs are characterized by reduced construction time, versatility, and easier space partitioning. Their structural behavior is not straightforward and, specifically, punching shear strength is a current research topic. In this study an experimental database of 113 RC slabs without shear reinforcement under punching loads was compiled using data available in the literature. A sensitivity analysis of the parameters involved in the punching shear strength assessment was conducted, which highlighted the importance of the flexural reinforcement that are not typically considered for punching shear strength. After a discussion of the current international standards, a new proposed model for punching shear strength and rotation of RC slabs without shear reinforcement was discussed. It was based on a simplified load-rotation curve and new failure criteria that takes into account the flexural reinforcement effects. This experimental database was used to validate the approaches of the current international standards as well as the new proposed model. The latter proved to be a potentially useful design tool.

关键词： punching shear strength     reinforced concrete     slabs     reinforcement ratio    

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标题 作者 时间 类型 操作

Investigation of the seismic behavior of grouted sandy gravel foundations using shaking table tests

Tiancheng WANG; Yu LIANG; Xiaoyong ZHANG; Zhihuan RUAN; Guoxiong MEI

期刊论文

厦门翔安海底隧道F1风化深槽注浆加固技术

郭小红,王梦恕

期刊论文

Effect of loading rate on shear strength parameters of mechanically and biologically treated waste

期刊论文

Experimental study on pile-end post-grouting piles for super-large bridge pile foundations

Weiming GONG, Guoliang DAI, Haowen ZHANG

期刊论文

Seismic performance of fabricated continuous girder bridge with grouting sleeve-prestressed tendon composite

期刊论文

Characterization of humic substances in bio-treated municipal solid waste landfill leachate

Guangxia QI, Dongbei YUE, Yongfeng NIE

期刊论文

A new automatic convolutional neural network based on deep reinforcement learning for fault diagnosis

期刊论文

84-month observational study of the changes in CD4 T-lymphocyte cell count of 110 HIV/AIDS patients treated

null

期刊论文

Evolution of composite fouling on a vertical stainless steel surface caused by treated sewage

Cheng ZAN, Lin SHI, Xiujuan MA, Wenyan YANG,

期刊论文

高压富水断层“外堵内固注浆法”设计新理念与工程实践

张民庆,张梅

期刊论文

Improved local control without elective nodal radiotherapy in patients with unresectable NSCLC treated

YANG Kunyu, LIU Li, ZHANG Tao, WU Gang, CAO Fengjun, WANG Jianhua

期刊论文

三峡升船机齿条及螺母柱间隙灌浆工艺试验

詹剑霞,李纪虎

期刊论文

Quantitatively assessing the pre-grouting effect on the stability of tunnels excavated in fault

Xiao YAN, Zizheng SUN, Shucai LI, Rentai LIU, Qingsong ZHANG, Yiming ZHANG

期刊论文

Analysis of cement-treated clay behavior by micromechanical approach

Dong-Mei ZHANG, Zhen-Yu YIN, Pierre-Yves HICHER, Hong-Wei HUANG

期刊论文

Punching of reinforced concrete slab without shear reinforcement: Standard models and new proposal

Luisa PANI, Flavio STOCHINO

期刊论文