On the behavior of the cured electroosmotic chemical treated clay     

Ou  Chang-Yu  Lin  Chien-Yu  Chien  Shao-Chi 《Acta Geotechnica》2020,15(8):2341-2354

Followed the proposed ECT procedure that was the injection of 0.75 M CaCl₂ solution for 72 h, then 1.5 M KOH solution for 48 h, then sodium silicate solution for 72 h and then deionized water for 168 h, the clay strength can be improved from anode to cathode entirely. To further improve the clay strength, curing the sample for different periods and applying electric field over the sample were studied. The cone resistance, water content, pH value, Ca²⁺ concentration and the XRD pattern were tested or analyzed in each test. Results show that injection of deionized water was a key phase to produce a full improvement of the treated clay, which cannot be replaced by the application of an electric field only and without injecting water. Curing the treated clay after injecting deionized water can yield a higher clay strength in the cathode area significantly due to pozzolanic reaction but produce a lower clay strength in the anode area because the formed NaOH decomposed the gel structure of the sodium silicate solution. To obtain a better strength after injection of deionized water for 168 h, the treated clay had to be cured for about 28 days, along with a dry anode compartment.

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Seismic performance analysis of BRBs and gussets in a full‐scale 2‐story BRB‐RCF specimen          下载免费PDF全文

Ching‐Yi Tsai  Keh‐Chyuan Tsai  Li‐Wei Chen  An‐Chien Wu 《地震工程与结构动力学》2018,47(12):2366-2389

The implementation of buckling‐restrained braces (BRBs) for new reinforced concrete frame (RCF) constructions is limited. This study investigates the seismic forces and stability in the BRBs and gussets of a 2‐story full‐scale RCF specimen by using Abaqus models and a newly proposed stability evaluation method. The hybrid and cyclic loading test results are accurately predicted by the Abaqus analyses. Existing methods for computing the gusset interface forces for steel buildings from both the brace and the frame actions are compared with the Abaqus results. The applicability of these methods for the BRB‐RCF design is critically evaluated. It is confirmed that the Parallel‐2 method is suitable for estimating the BRB force demand imposed on the corner gusset and the generalized uniform force method is good for the corner gusset at the base. In addition, existing stability evaluation methods for BRBs and gussets are applied to investigate the out‐of‐plane (OOP) buckling of the first‐story BRB observed at the end of tests. The proposed stability model incorporates the BRB restrainer's flexural effects and 4 rotational springs in assessing the BRB's buckling. This model confirms that the BRB and the gusset's OOP buckling limit states could be coupled and must be evaluated together. By incorporating the flexural effects of the steel casing and the infilled grout, the proposed model satisfactorily predicts the OOP buckling of the first‐story BRB and gussets. These research results can be used for the implementation of BRBs in new RC frame constructions.  相似文献   

四川九寨沟M_S7.0地震序列视应力时空特征     

邱玉荣  刘春  杨宜海  邵辉成  石军  石富强  刘洁 《中国地震》2017,33(4):511-520

利用中国测震台网记录到的数字地震波形资料,通过波形分析和反演,获得了2017年8月8日四川九寨沟7.0级地震序列的视应力。研究表明:(1)在震后早期阶段九寨沟地震序列视应力水平较高,主震发生后不到1天视应力开始下降,主震发生1周后基本稳定,略有起伏;(2)震源区应力状态存在时空分段差异,余震区东南段视应力下降较快,而西北段下降较缓,最大余震发生前,东南段视应力水平略高或相当于西北段,最大余震发生至震后70天,西北段视应力水平高于东南段,这可能与余震区东南段比西北段破裂充分有关;(3)最大余震发生在主震震中东南侧视应力较高的区域,高视应力余震位于主震震中两侧靠近端部,与主震双侧扩展端部应力相对集中的结果一致。  相似文献   

Terrain attributes of earthquake‐ and rainstorm‐induced landslides in orogenic mountain Belt,Taiwan          下载免费PDF全文

Jr‐Chuan Huang  John D. Milliman  Tsung‐Yu Lee  Yi‐Chin Chen  Jiin‐Fa Lee  Cheng‐Chien Liu  Jiun‐Chuan Lin  Shuh‐Ji Kao 《地球表面变化过程与地形》2017,42(10):1549-1559

Landsliding induced by earthquakes and rainstorms in montane regions is not only a sculptor for shaping the landscape, but also a driver for delivering sediments and above‐ground biomass downstream. However, the terrain attributes of earthquake‐ and rainstorm‐induced landslides are less discussed comprehensively in Taiwan. As part of an island‐wide inventory, we here compare and contrast the landslide terrain attributes resulting from two catastrophic events: the Chi‐Chi earthquake (M _w = 7.6, September 1999) and typhoon Morakot (rainfall >2500 mm, August 2009). Results show that the earthquake‐induced landslides are relatively small, round‐shaped and prone to occur primarily in middle and toe of slopes. In contrast, the rainstorm‐induced landslides are larger, horseshoe‐shaped and preferentially occurring in slope toes. Also, earthquake‐induced landslides, particularly large landslides, are usually found at steeper gradients, whereas rainstorm‐induced landslides aggregate at gradients between 25° and 40°. Lithologic control plays a secondary role in landsliding. From an island‐wide perspective, high landslide density locates in the region of earthquake intensity ≥ VI or one‐day rainfall ≥600 mm day^?1. Through the landslide patterns and their terrain attributes, our retrospective approach sheds light on accessing the historical and remote events for close geophysical investigations. Finally, we should bear in mind that the landslide location, size, and terrain attributes varying with triggers may affect the landscape evaluation or biogeochemical processes in landslide‐dominated regions. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

A model for analyzing the transshipment competition relationship between the port of Hong Kong and the port of Kaohsiung     

Chien Chang Chou 《中国海洋大学学报(英文版)》2009,8(4):377-384

The transshipment is an important issue in the current marine transportation. This paper constructed a mathematical programming model to elaborate the transshipment port selection for the shipping company. This model is tested by the data collected from the ports of Hong Kong and Kaohsiung. The results show that this model can be used to explain the transshipment competition relationship between the ports of Hong Kong and Kaohsiung well. A sensitivity analysis was also executed. The sensitivity analysis results showed that both the port of Hong Kong and Kaohsiung should decrease the charges of port and increase the efficiency of loading and discharging. Based on the sensitivity analysis results, some interesting conclusions and helpful suggestions were obtained for the managers of the ports of Hong Kong and Kaohsiung to improve their port management.  相似文献   

基于气候模式筛选的碧流河水库流域未来期径流预估研究     

梁满营  李昱  周惠成 《水文》2018,38(4):6-11

为评估IPCC第四次评估报告中的15个全球气候模式对碧流河水库流域气温和降水的模拟效果,通过LARS-WG降尺度方法,选取了HADCM3等3种气候模式,分析其在A2、A1B和B1三种排放情景下未来期(2011~2040年)碧流河水库流域气温和降水的变化,进而结合ABCD月尺度水文模型,预估未来气候变化下碧流河水库流域的径流变化特征,为流域水资源规划和管理提供依据。结果表明:CNCM3、HADCM3和IPCM4三个模式对碧流河水库流域模拟效果较好;与基准期相比,未来期多年平均降水变幅为-6.4%~3.7%,多年平均温度升高0.8℃~1.2℃,实际蒸发增幅为2.4%~4.4%;多年平均年径流量变化范围为4.8~6.2(108m3),三种排放情景下各模式平均径流量均呈减少趋势,较基准期减幅为-4.7%~-27.1%,未来水资源利用将会面临更大挑战。  相似文献   

Evidence that earthquakes have been triggered by reservoir in the Song Tranh 2 region,Vietnam     

Thai Anh Tuan  N. Purnachandra Rao  Kalpna Gahalaut  Cao Dinh Trong  Le Van Dung  Cao Chien  K. Mallika 《Journal of Seismology》2017,21(5):1131-1143

In the Song Tranh 2 (ST2) hydropower reservoir located in the Quang Nam province, Central Vietnam, earthquakes started occurring soon after impoundment of the reservoir in late 2010. Earthquakes continue to occur in the region, and two earthquakes of M 4.6 and 4.7 on October 22, 2012 and November 15, 2012, respectively, have been reported (Trieu et al. 2014; Giang et al. 2015) in the vicinity of the reservoir. In the present study, b-value has been estimated, and focal mechanism solutions have been computed for the first time using moment tensor inversion approach. Also, the influence of impoundment of reservoir on the occurrence of earthquakes has been computed for the ST2 region based on Coulomb stress. A quality data set of 595 earthquakes recorded for the period of October 2012 to April 2014 at ten stations of the seismic network operated by the Institute of Geophysics (IGP) has been used to calculate b-values for the northern and southern seismicity clusters of the region. In general, the b-values associated with reservoir-triggered seismicity (RTS) are found to be higher than the regional b-values in the frequency-magnitude relation of earthquakes. For the ST2 region, it is found that the b-values for the northern and southern clusters are 0.94 ± 0.04 and 0.90 ± 0.04, respectively. Focal mechanism solutions obtained for the two earthquakes close to the reservoir have a right-lateral strike-slip mechanism, with the preferred planes trending NW-SE. These results are concurrent with the orientation of the nearby local surface faults, which we confirm as the active faults in this region. Influence of the stresses due to reservoir water load on the local seismicity is computed based on the obtained focal mechanism by using the concept of fault stability. It is found that most of the earthquakes occur in the positive Coulomb stress region, which shows the influence of reservoir impoundment on earthquake occurrence in the vicinity. Our results suggest that the local earthquakes are triggered by the impoundment of the ST2 reservoir.  相似文献   

Soil improvement of electroosmosis with the chemical treatment using the suitable operation process     

Shao-Chi Chien  Fu-Chen Teng  Chang-Yu Ou 《Acta Geotechnica》2015,10(6):813-820

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大凌河流域上游水资源变化趋势及成因研究   总被引：2，自引：1，他引：1  

张丹  周惠成 《水文》2011,(4):81-87

R/S和Mann-Kendall都是用来研究径流和降雨变化的常用方法,R/S方法可以揭示序列的水文特征和变异点,但不能说明研究对象未来的变化趋势;Mann-Kendall可以检验水文序列趋势和变化的程度,但不能预测水文时间序列未来的趋势特征。针对R/S和Mann-Kendall法在水文变化趋势分析中的优点和不足,提出了二者相结合的水文变化趋势特征分析,并将其应用于大凌河流域上游的水资源变化趋势分析中。研究表明,R/S和Mann-Kendall综合分析法较好地揭示了降水和径流的变异点,也揭示出降水变化趋势不明显,径流呈现较为显著的下降趋势。本文对径流和降水不对称的相应关系及其成因进行了分析,得出流域内大量的水利工程截留和人类活动取用水成为径流显著下降的主要驱动因素。  相似文献   

Characteristics and possible origin of native aluminum in cold seep sediments from the northeastern South China Sea     

Zhong Chen  Chi-Yue Huang  Meixun Zhao  Wen Yan  Chih-Wei Chien  Muhong Chen  Huaping Yang  Hideaki Machiyama  Saulwood Lin 《Journal of Asian Earth Sciences》2011,40(1):363-370

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