Liquefaction evaluation of dam foundation soils considering overlying structure

Gng Wng,Xing Wei,Hnlong Liu

aSchool of Civil Engineering,Chongqing University,Chongqing 400044,China

bSchool of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China

Liquefaction evaluation of dam foundation soils considering overlying structure

Gang Wanga,*,Xing Weib,Hanlong Liua

aSchool of Civil Engineering,Chongqing University,Chongqing 400044,China

bSchool of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China

A R T I C L E I N F O

感染的子宮內(nèi)膜組織中有淋巴細(xì)胞和巨噬細(xì)胞浸潤(rùn)的慢性炎癥反應(yīng),這種慢性潛伏性感染對(duì)子宮內(nèi)膜產(chǎn)生有害的炎癥反應(yīng)、免疫系統(tǒng)活動(dòng)及產(chǎn)生的抗解脲支原體細(xì)胞因子,損害生長(zhǎng)中的胚胎或干擾胚胎植入,也可能干擾自體免疫系統(tǒng),保護(hù)胚胎的調(diào)節(jié)機(jī)制,導(dǎo)致流產(chǎn)的發(fā)生[7,8]。但目前認(rèn)為,生殖道僅有支原體寄生并不引起不良的妊娠結(jié)局。

Article history:

Received 9 December 2014

Received in revised form

4 February 2015

既然耐密型玉米品種增產(chǎn)潛力巨大，科研單位就要增加耐密型玉米科研經(jīng)費(fèi)，改變研究方向，多出耐密型品種，限制稀植大穗品種數(shù)量。種子生產(chǎn)單位也要轉(zhuǎn)變生產(chǎn)理念，多生產(chǎn)耐密型品種，減少稀植大穗品種的生產(chǎn)計(jì)劃。種子經(jīng)銷(xiāo)商按照市場(chǎng)的供給與需求，調(diào)整經(jīng)營(yíng)策略，增加耐密型玉米種子的供給，從源頭上改種耐密型品種。

Accepted 5 February 2015

Available online 25 February 2015

Liquefaction

Overlying structure

Dam

Stone columns

The liquefaction analysis procedure conducted at a dam foundation associated with a layer of lique f able sand is presented.In this case,the effects of the overlying dam and an embedded diaphragm wall on liquefaction potential of foundation soils are considered.The analysis follows the stress-based approach which compares the earthquake-induced cyclic stresses with the cyclic resistance of the soil,and the cyclic resistance of the sand under complex stress condition is the key issue.Comprehensive laboratory monotonic and cyclic triaxial tests are conducted to evaluate the static characteristics,dynamic characteristics and the cyclic resistance against liquefaction of the foundation soils.The distribution of the factor of safety considering liquefaction is given.It is found that the zones beneath the dam edges and near the upstream of the diaphragm wall are more susceptible to liquefaction than in free f eld,whereas the zone beneath the center of the dam is less susceptible to liquefaction than in free f eld.According to the results,the strategies of ground improvement are proposed to mitigate the liquefaction hazards.

?2015 Institute of Rock and Soil Mechanics,Chinese Academy of Sciences.Production and hosting by Elsevier B.V.All rights reserved.

1.Introduction

whereτmaxis the peak value of horizontal shear stress,andσ′v0is the vertical effective consolidation stress.The time history of earthquake-induced cyclic stress involves numerous irregular cycles of different amplitudes.Various studies showed that an irregular time history can be approximated by a uniform cyclic stress time history with an equivalent number of uniform cycles depending on the uniform cyclic stress amplitude.Commonly,a representative value(or equivalent uniform value)equal to 65%of the peak cyclic stress is adopted as the amplitude of the equivalent uniform cyclic stress series.

Furthermore,Fig.10 presents the distribution of the factor of safety against liquefaction on the middle plane of the sand layer subjected to earthquake of intensity VIII.The peak acceleration of intensity VIII is about 219 cm/s2.The minimum value of the factor of safety beneath the dam is only 0.7.Fig.10 indicates that the sand layer in the overall dam site would trigger liquefaction when subjected to an earthquake of intensity VIII.

Although some advances have been made on seismic liquefaction assessment of foundation soils beneath structures,to consider the effect of overlying structures on liquefaction evaluation still remains a controversial and dif f cult issue.The effect of structures on the liquefaction potential of foundation soils depends on both the characteristics of structures and soils,so direct applicability of the simpli f ed methods(e.g.Seed-Idriss procedure or Chinese simpli f ed procedure)to foundation soils beneath structures is impossible,unless the soil-structure-earthquake interaction is reliably addressed in the estimation of cyclic stress ratio(CSR) (Cetin et al.,2012).Numerical method can not only consider almost all the factors in f uencing the interaction between structures and subsoils but also be an ef f cient way to solve this problem.The key problem in numerical method is the criterion for judging liquefaction triggering in complex stress conditions.To illustrate these trivial but essential matters in the numerical method,the liquefaction analysis procedure of a practical case,a dam built on the foundation with a lique f able sand layer,is presented.The procedure includes two aspects:(1)detailed f eld exploration and comprehensive laboratory tests to determine the criterion for liquefaction triggering of the sand layer,and(2)3D f nite element analysis to calculate the static and dynamic interaction between the dam and underlying soils.

It should be noted that some exciting progress has been achieved in the aspects of constitutive modeling of sand and the codes for fully coupled dynamic response analysis of saturated porous media(Wang and Zhang,2007;Wang et al.,2011;Zhang and Wang, 2012).The whole liquefaction process,including the onset of liquefaction,the process of generation,diffusion and release of excess pore water pressure,and even the development of liquefaction-induced deformation,can be simulated by the fully coupled dynamic numerical methods.The whole liquefaction process simulation involves comprehensive constitutive models with complicated codes of fully coupled dynamic consolidation and large amount of testing work(e.g.Zhang and Wang,2012).As a result,it is not very appealing and sometimes impractical for small engineering projects.The procedure adopted in this study intends to overcome these issues,so that it would be ef f cient and economical for middle or small projects.

2.A sluice dam in China

A typical sluice dam in China is taken as an example to illustrate the procedure for liquefaction assessment.This type of dam is not very high,and natural deposits are usually taken as the foundation. As shown in Fig.1,the dam is composed of four sluice segments in the middle of the river and two gravity dam segments located at the left and right abutments,respectively.The sluice segments are 27.5 m in height.The alluvial deposits underlying the sluice segments are from 35 m to 47 m in depth.The deposits are composed of 3 layers.The soils from top to bottom are gravel,sand and gravel, respectively.The sand layer is 5-10 m in thickness,and is distributed all over the dam site.

4.4.Suggestions for ground improvement

3.Numerical procedure for liquefaction evaluation

The stress-based approach compares the earthquake-induced CSR with the cyclic resistance ratio(CRR)of the soil to judge whether liquefaction would be triggered.The factor of safety(FS)against the triggering of liquefaction can then be computed as the ratio of the sand’s CRR to the earthquakeinduced CSR:

Fig.1.Geological pro f le of the dam foundation.(a)Longitudinal section,and(b)Transverse section.

Based on empirical correlations of some observed performance of“l(fā)iquefaction/non-liquefaction”case histories,several simpli f ed approaches employing in situ test indices have been developed for assessing liquefaction potential of soils(Seed and Idriss,1971;Seed, 1979).These simpli f ed approaches can only be used to evaluate liquefaction triggering for level or nearly level free f eld ground without structures.While in practice these simpli f ed approaches were widely used to evaluate the liquefaction potential of soils beneath or near a structure,the soils beneath a structure are treated as if they are in the free f eld under level ground conditions and the effect of the buildings resting on the ground surface is ignored.

3.1.Estimating earthquake-induced CSR

4.1.FEM model

The earthquake-induced CSR can be estimated via the Seed-Idriss simpli f ed procedure(Seed and Idriss,1971)or numerical methods such as f nite element method(FEM)-based seismic response analysis.Seed-Idriss simpli f ed procedure can only be used to estimate the earthquake-induced cyclic stresses beneath level ground sites without structures subjected primarily to horizontal shaking.In this case,there exists a dam overlying on the surface of the ground and a diaphragm wall embedded in the foundation soil,so at least two factors would alter the CSR of the underground deposits induced by earthquake shaking.The two factors are the change in vertical effective stress induced by the dam load and the in f uence of response interaction between the dam and the subsoils.In addition to these factors,a two-step analysis procedure is adopted.Firstly,a static analysis is conducted to obtain the initial static stress before earthquake.The process of the dam construction and reservoir f lling are modeled.And then,speci f ed earthquake acceleration time history is input to the FEM model to obtain the dynamic stresses of the foundation soils.

In static stress analysis,Duncan and Chang(1970)’s model is adopted for constitutive description of foundation soils.Four monotonic triaxial drained compression tests are conducted to determinate the parameters of Duncan and Chang’s model,in which isotropically consolidated undrained(ICU)samples are adopted with initial con f ning pressureσ3cof 100 kPa,200 kPa, 400 kPa and 800 kPa,respectively.The height and the diameter of the sand samples are 8 cm and 3.8 cm,respectively.The samples have a relative density of 50%(i.e.an initial dry density of 1.47 g/ cm3)and are saturated by vacuum method.The model parameters for foundation soils determined by these triaxial tests are shown in Table 1.

那邊觀戰(zhàn)的老板娘卻不愿意了，停下剔指甲的手，朝堂下看過(guò)來(lái)，柔聲埋怨老黃：“你們花錢(qián)請(qǐng)我來(lái)做這個(gè)掌柜，就得愛(ài)惜這個(gè)店子啊，難道今年賺了錢(qián)，明年就關(guān)門(mén)么？你們的命不值錢(qián)，你們頭上的面具可都是傳了好幾百年的，打破了多可惜！你們扮山賊倒是十足，一個(gè)個(gè)像由十二連環(huán)塢出來(lái)的！”

The dynamic response analysis is based on the technology of equivalent linear procedures.The nonlinear cyclic stress-strain characteristics are approximated by an equivalent modulusG/Gmaxand damping ratioλ,whereGis the dynamic shear modulus andGmaxis the maximum dynamic shear modulus.BecauseG/Gmaxand λvary with the amplitude of the cyclic shear strainγ,two groups of resonant column tests are conducted to determine the relationship betweenG/Gmaxandλchanging with shear strain of the sand layer, in which anisotropically consolidated undrained(ACU)sample with stress ratioσ1c/σ3c=2.0 and two levels of con f ning pressureσ3c(100 kPa and 400 kPa)are adopted,whereσ1cis the axial consolidation stress.The con f ning pressure and the stress ratio are selected according to the range of the in situ static stress before and after the construction of the dam.The sand specimens in resonant column tests have a height of 10 cm,a diameter of 5 cm and a relative densityDrof 50%.According to the results of resonant column tests,the maximum dynamic shear modulus of the sand can be determined by mean effective stress asGmax=800（p/pa）0.5, wherepis the mean effective stress andpais the atmospheric pressure(=101 kPa).The resonant column tests also present the relationship of dynamic shear modulus ratio and damping ratio changing with dynamic shear strain,as shown in Fig.2.In the analysis,the values of shear modulus and damping ratio are determined by iterations so that they become consistent with the level of shear strain induced in each element.

Table 1Duncan and Chang model’s parameters of foundation soils.

3.2.Evaluating CRR of sand

There are mainly two approaches to estimate the CRR of saturated sands.One approach is testing the specimens in cyclic laboratory tests and the other is through semi-empirical correlations between in situ CRR and the in situ test indices.Although the in situ tests widely used to evaluate liquefaction characteristics include SPT,cone penetration test(CPT),back pressure test(BPT),large penetrometer test(LPT),and shear wave velocity(Vs)test,these correlations between CRR and in situ test indices are developed mainly based on the case histories of the free-f eld,level ground conditions.In this case,inside the foundation soils,there exist initial static shear stresses on horizontal planes,and the con f ning pressures and over-consolidation ratio are changed due to the overlying dam.For these reasons,the CRR of the soils beneath or near the dam could be different from the CRR of the soils under the free-f eld,level ground conditions.So the CRR estimated by the semi-empirical correlations based on in situ test indices should be corrected accordingly.

Fig.2.The change of modulus and damping ratio of the sand with shear strain.

Due to the differences in consolidation stress state between cyclic triaxial tests and f eld conditions,the CRR measured in cyclic triaxial tests should be corrected for f eld conditions as follows (Ishihara et al.,1985):

Fig.3.Cyclic resistance of the sand vs.number of cycles.

The effect of a static shear stress on the CRR of sand depends on initial static shear stress ratio,relative density,con f ning stress,etc. Different initial consolidation stress ratios in triaxial tests result in different magnitudes of static shear stress on the 45°plane of the specimen.Fig.3 shows the CRR at two different con f ning stresses and two different consolidation stress ratios.The consolidation stress ratio can be converted to the initial static shear stress ratio on the 45°plane.In the analysis,the CRR of each element of soil is determined by interpolation in the results(see Fig.3)according to the initial consolidation stress and initial static shear stress ratio of the element.

3.3.CSR of sand in composite foundations

編實(shí)編強(qiáng)骨干隊(duì)伍。原則上控制民兵網(wǎng)軍力量保持現(xiàn)有規(guī)模不再擴(kuò)大，重點(diǎn)在編實(shí)編強(qiáng)隊(duì)伍上下功夫。打破現(xiàn)行民兵編組在人員來(lái)源、年齡劃段等方面的常規(guī)做法，提高專(zhuān)業(yè)實(shí)踐能力的編兵權(quán)重，專(zhuān)業(yè)技術(shù)崗位對(duì)口率不低于90%。拓寬人員來(lái)源渠道，積極向職業(yè)技術(shù)院校、IT企業(yè)、金融、電商、民生基礎(chǔ)設(shè)施等企事業(yè)單位延伸。積極探索合作育人、訓(xùn)編一致的編組方法，與高等院校、行業(yè)企業(yè)等建立培訓(xùn)合作機(jī)制，鼓勵(lì)資助在校學(xué)生參加網(wǎng)安人才定向培養(yǎng)，預(yù)編進(jìn)入民兵隊(duì)伍。堅(jiān)持“實(shí)戰(zhàn)技能優(yōu)先、專(zhuān)業(yè)對(duì)口優(yōu)先、思想道德優(yōu)先”的原則，把政治素質(zhì)高、專(zhuān)業(yè)技術(shù)精、組織能力強(qiáng)的人員吸納進(jìn)入民兵網(wǎng)軍隊(duì)伍。

The method of vibro-replacement stone columns was proposed to improve the lique f able sand layer.The improved foundation is composed of stone columns and the sand.In the FEM analysis,the composite foundation is assumed homogeneous.Based on the principle of deformation consistency,the modulus of the composite foundationEspcan be approximated by the following formula,as suggested by GB 50007-2002(MOHURD,2002):

巴金的寫(xiě)作風(fēng)格就是樸素，他娓娓道來(lái)，看似漫不經(jīng)心，卻暗含匠心。他的語(yǔ)言平實(shí)，我們讀起來(lái)沒(méi)有障礙，也容易被感染，這就是巴金的風(fēng)格，大家的風(fēng)范。這么沉重的主題卻是通過(guò)小事去寫(xiě)，寫(xiě)得明白，寫(xiě)得曉暢，這正適合我們通過(guò)引導(dǎo)學(xué)生解讀文本來(lái)了解背景，以此來(lái)加深對(duì)文章的理解，對(duì)作者情感的把握，對(duì)文章主旨的領(lǐng)悟。

在變式過(guò)程中，不論習(xí)題怎么變化，總體方向都應(yīng)該以考試說(shuō)明為主.不能為了改變而改變，導(dǎo)致最后出來(lái)的題目與考試內(nèi)容無(wú)關(guān)，這樣不僅浪費(fèi)了學(xué)生的時(shí)間，還可能會(huì)打擊學(xué)生學(xué)習(xí)的積極性.

That is to say,the stress of the sand is the stress of the composite foundation divided by the reinforcement coef f cient.Because the consolidation process of the soil deposit under gravity-driven load has completed,the initial geostatic stress of the soil is kept in the sand.The dam is constructed after the foundation improvement,so the additional vertical stress of the sand due to the dam load should be reduced.Consequently,the cyclic stress ratio of the sand layer (CSRs)can be calculated as

whereσv,spis the effective vertical stress of the composite foundation,andσvs,0is the initial effective vertical stress of the natural soil deposits before dam construction.

4.Results and discussion

麥小秋沒(méi)有想到汪小波的歌唱得那樣好。走進(jìn)“川上川”，先是麥小秋握住了話(huà)筒，汪小波聽(tīng)著，在每首歌之后為她鼓掌，后來(lái)她把話(huà)筒遞給了汪小波。汪小波簡(jiǎn)直就是受過(guò)訓(xùn)練的男中音，他唱了光頭李進(jìn)的《你在他鄉(xiāng)還好嗎》，楊坤的《無(wú)所謂》。推向高潮的是閆維文唱火的那首《母親》，“你上學(xué)的小書(shū)包有人給你拿，你遮雨的花折傘有人為你打，你愛(ài)吃的三鮮餡有人為你包，你委屈的淚花兒有人給你擦。啊，這個(gè)人就是娘啊，這個(gè)人就是媽?zhuān)∵@個(gè)人給了我生命，給我一個(gè)家……”歌聲使麥小秋有了淚花，看見(jiàn)了村西的滄河，看見(jiàn)了母親。她慢慢靠近了汪小波，而且伸開(kāi)雙臂，頓住腳，幾乎是喃喃地，說(shuō)：“能抱抱嗎？”

The 3D discretized meshes of the sluice dam and foundation are illustrated in Fig.4.Three stages are simulated in static analysis:(1) the diaphragm wall completed;(2)the dam and sluice completed; and(3)reservoir f lling to normal pool level.The stress condition at stage 3 is assumed as the initial stress condition for seismic response analysis.According to the earthquake risk assessment report issued by China Earthquake Administration(CEA),the seismic precautionary intensity at the dam site is VII degree,and the peak acceleration at base rock surface is 106 cm/s2.The input earthquake wave is shown in Fig.5,which is arti f cially generated by CEA with the predominant period of the input earthquake of about 0.2 s.According to theSpecifcations for Seismic Design of Hydraulic Structures(DL 5073-2000)(IWHR,2000),the basic designed seismic intensity of the dam is equal to the seismic precautionary intensity at the dam site(i.e.VII),and the dam design should be checked in accordance with earthquake intensity of VIII, which have a peak acceleration of about 219 cm/s2given by CEA.

4.2.Initial conditions before earthquake

（3）底質(zhì)有機(jī)質(zhì)污染。水產(chǎn)養(yǎng)殖區(qū)域底質(zhì)中氮、磷、硫等有毒有害物質(zhì)在底質(zhì)中富集，部分釋放到水體，引起水體的富營(yíng)養(yǎng)化。

Fig.4.3D f nite element mesh of dam and foundation.

Fig.5.Input earthquake wave(intensity VII).

4.3.Cyclic stresses and liquefaction potential

Fig.6.The distribution of static stresses of the sand layer(unit:kPa).

Fig.7 shows the cyclic stress time history of a typical element of sand subjected to an earthquake of intensity VII.According to Fig.7, the time history of equivalent uniform cyclic stress of 65%peak cyclic stress with an equivalent number can be determined.The equivalent number of cycles mainly depends on earthquake magnitude.In this case,an earthquake magnitude of 7.5 with 15 equivalent cycles is assumed based on the empirical relationships(Green and Terri,2005).Fig.8 presents the peak cyclic shear stress on the middle horizontal plane of the sand layer.The shear stress beneath and near the dam is obviously larger than that in other zones.Fig.9 shows the distribution of the factor of safety against liquefaction on the middle plane of the sand layer.In the sand layer, the minimum value of theFSbeneath the dam is about 1.25,but near the upstream and downstream edges of the dam theFSis less than 1.0,suggesting that the liquefaction would be triggered in this zone.In the edge of the dam vertical effective stress is relatively small and the cyclic shear stress induced by earthquake is relatively large,so in this region the CSR is large and exceeds the CRR.It should be also noticed from Fig.8 that the horizontal normal stress of the sand near the upstream side of the diaphragm wall is small, so the liquefaction resistance in this area apparently decreases.

Field case histories,model tests and numerical analysis suggested that conditions in f uencing liquefaction near a structure may be substantially different fromthose for the same soil pro f le in the free f eld.Although the in f uence of structures on potential liquefaction damage has not been well understood,the following conclusions can be drawn(Liu and Qiao,1984;Rollins and Seed, 1990;Cetin et al.,2012).(1)The excess pore water pressure distribution near a building can be much different from that in the free f eld.(2)The liquefaction potential of soil may be greater or lesser beneath a structure,depending mainly on the structure type and soil density.For instance,sands underneath low-rise and shortperiod structures appear to have higher liquefaction potential, while sands underneath tall and long-period structures appear to have lower liquefaction potential than in the free-f eld.(3)The ground under the edges of a structure is more susceptible to triggering liquefaction than that under the center of the structure. Some modi f cations were suggested for the free-f eld liquefaction evaluation procedure to account for the structure effects.Men et al. (1998)proposed a simple method to evaluate dynamic stress of the ground exerted by aboveground structures,and developed a simpli f ed method to evaluate liquefaction of building’s subsoils. Jing et al.(2001)further considered the subsoil’s nonlinearity in the framework of the method proposed by Men et al.(1998).Yang et al. (2010)adopted an equivalent in f uence depth to consider additional stress exerted by a f nite building base,and revised the standard penetration test(SPT)-based method adopted by Chinese code GB 50287-2008(MOHURD,2008).Noorzad et al.(2009) evaluated the effect of structures on the wave-induced liquefaction potential of seabed by applying a structure force on the underlying sand deposits.Based on numerical results of generic soils, structure and earthquake combinations,Cetin et al.(2012)developed an alternative simpli f ed procedure for three-dimensional(3D)dynamic response assessment of soil and structure systems, which can produce unbiased estimates of the representative and maximum soil-structure-earthquake-induced cyclic stress ratio values.Meanwhile,Oka et al.(2012)considered the effect of heavy structures on the liquefaction potential of the foundation soils by incorporation of mean stresses in the framework of the simpli f ed procedure.

Fig.7.Time history of cyclic shear stress of typical element in sand layer.

By using the presented method,the distribution of the factor of safety against liquefaction can be given.Thus different design parameters for ground improvement can be assumed for different zones.For this project,the ground improvement should be focused on the upstream side of the diaphragm wall and the edges of the dam.The simpli f ed method suggested by GB 50287-2008 (MOHURD,2008)does not always produce conservative estimates of the liquefaction triggering response and it may miss the most susceptible regions.

Fig.8.Contours of peak shear stress of sand layer(unit:kPa).

Fig.9.Contours of factor of safety against liquefaction in sand layer(intensity VII).

Fig.10.Contours of factor of safety against liquefaction in sand layer(intensity VIII).

5.Conclusions

The gate–source capacity Cgs/L was calculated as below:

Liquefaction analysis of foundation soils of a building is much different from free-f eld ground,and must consider the interaction between building and subsoils.The liquefaction potential of the subsoils beneath a building depends on both the characteristics ofthe building and the subsoils.The numerical method and codes involved in the present procedure are promising,and the amount of test works is acceptable for most engineering projects,thus the procedure can be suggested for most practical engineering problems.As stated above,the criterion for liquefaction triggering under complex stress conditions is the key problem of the present procedure,and it determines the reliability of the results.Therefore, the cyclic resistance of lique f able soil should be carefully estimated through f eld investigation,laboratory tests and experiences.

對(duì)于我來(lái)說(shuō)，除了家里的書(shū)房，單位的辦公室也成了書(shū)房。那里有兩個(gè)書(shū)柜，當(dāng)然也是貴客滿(mǎn)盈，待遇差一點(diǎn)的，只好屈就于書(shū)柜兩側(cè)，高高摞起，一排不成，兩排——由于摞得太高，有搖搖欲墜之勢(shì)。還好，至今尚未發(fā)生坍塌事故。所以，可以說(shuō)，我的書(shū)房只是一個(gè)大本營(yíng)，一個(gè)基地，書(shū)早已突破了它的拘囿，隨處可在。

Con f ict of interest

The authors wish to con f rm that there are no known con f icts of interest associated with this publication and there has been no signi f cant f nancial support for this work that could have in f uenced its outcome.

Acknowledgments

The authors appreciate the support from the National Natural Science Foundation of China(No.51209179).

商業(yè)銀行理財(cái)產(chǎn)品的類(lèi)別化是實(shí)現(xiàn)“功能性金融監(jiān)管”的基礎(chǔ)。目前，針對(duì)商業(yè)銀行理財(cái)產(chǎn)品的分類(lèi)標(biāo)準(zhǔn)很多，分類(lèi)方法各不相同，一定程度上造成了理財(cái)產(chǎn)品劃分上的混亂。事實(shí)上，對(duì)現(xiàn)有產(chǎn)品進(jìn)行合理分類(lèi)，一方面有利于確定法律關(guān)系，明確各方權(quán)利義務(wù)；另一方面也有利于評(píng)估風(fēng)險(xiǎn)，并進(jìn)行合理地風(fēng)險(xiǎn)匹配和有效地監(jiān)管。根據(jù)《商業(yè)銀行個(gè)人理財(cái)業(yè)務(wù)管理暫行辦法》的規(guī)定，按照客戶(hù)獲取收益的方式不同，理財(cái)產(chǎn)品可分為保本固定收益產(chǎn)品、保本浮動(dòng)收益產(chǎn)品與非保本浮動(dòng)收益產(chǎn)品三類(lèi)。這一分類(lèi)有利于消費(fèi)者明晰理財(cái)產(chǎn)品收益情況和維護(hù)自身利益，有利于監(jiān)管者針對(duì)不同類(lèi)型的理財(cái)產(chǎn)品采取相應(yīng)的監(jiān)管措施，可以滿(mǎn)足金融微觀監(jiān)管的需求。

Cetin K,Unutmaz B,Jeremic B.Assessment of seismic soil liquefaction triggering beneath building foundation systems.Soil Dynamics and Earthquake Engineering 2012;43:160-73.

China Institute of Water Resources and Hydropower Research(IWHR).Speci f cations for seismic design of hydraulic structures(DL 5073-2000).Beijing:China Electric Power Press;2000(in Chinese).

Duncan JM,Chang CY.Nonlinear analysis of stresses and strains in soils.Journal of Soil Mechanics and Foundation Division,ASCE 1970;96(5):1629-53.

Green RA,Terri GA.Number of equivalent cycles concept for liquefaction evaluations-revised.Journal of Geotechnical and Geoenvironmental Engineering, ASCE 2005;131(4):477-88.

Ishihara K,Yamazaki A,Haga K.Liquefaction ofK0-consolidated sand under cyclic rotation of principal stress direction with lateral constraint.Soils and Foundations 1985;5(4):63-74.

Jing LP,Chen WH,Ge LC.A simpli f ed method for evaluating liquefaction of building’s subsoil with consideration of nonlinear constitutive relationship. Earthquake Engineering and Engineering Vibration 2001;21(2):121-5(in Chinese).

Liu H,Qiao T.Liquefaction potential of saturated sand deposits underlying foundation of structure.In:Proceedings of the 8th World Conference on Earthquake Engineering.San Francisco,USA:Prentice-Hall,Inc.;1984.p.199-206.

Based on the stress criteria and seismic response analysis,the liquefaction potential of a lique f able foundation overlying a sluice dam is evaluated.A 3D FEM model including the dam and foundation is established,thus both the static and dynamic interaction effects between the dam and foundation are considered in the calculated CSR of the foundation.The results show that(1)the soil near the edges of the dam is more prone to liquefy than that beneath the center of the dam,and(2)the simpli f ed liquefaction evaluation procedure proposed by GB 50287-2008(MOHURD, 2008)is conservative for the soil beneath the center of the dam, and unsafe for the soil near the edges of the dam.The procedure presented in this study can give the distribution of the safety factor against liquefaction,depending on site-speci f c boundary conditions.The foundation soil can be zoned according to the distribution of the factor of safety,so the countermeasures for ground improvement may be more ef f cient.

Men FL,Cui J,Jing LP,Chen WH.A simpli f ed method to evaluate liquefaction of building’s subsoil.Chinese Journal of Hydraulic Engineering 1998;29(5):33-8 (in Chinese).

Ministry of Housing and Urban-Rural Development of the People’s Republic of China(MOHURD).Code for geological investigation of water resources and hydropower engineering(GB 50287-2008).Beijing:China Planning Press; 2008(in Chinese).

Ministry of Housing and Urban-Rural Development of the People’s Republic of China(MOHURD).Code for design of building foundation(GB 50007-2002). Beijing:China Architecture and Building Press;2002(in Chinese).

Noorzad R,Safari S,Omidvar M.The effect of structures on the wave-induced liquefaction potential of seabed sand deposits.Applied Ocean Research 2009;31(1):25-30.

Oka LG,Dewoolkar MM,Olson SM.Liquefaction assessment of cohesionless soils in the vicinity of large embankments.Soil Dynamics and Earthquake Engineering 2012;43:33-44.

有人說(shuō)：“有生之年，一定要去臺(tái)北跨一次年?！睕](méi)錯(cuò)，和眾人一起歡呼、共賞絕世美景的體驗(yàn)，一定是在KTV包廂里歡聚，或宅在家里看跨年晚會(huì)所不能比擬的。這個(gè)春節(jié)，就來(lái)臺(tái)北，讓自己和家人平淡的日子徹底綻放一次吧。

Rollins KM,Seed HB.In f uence of building on potential liquefaction damage.Journal of Geotechnical Engineering 1990;116(2):165-85.

Seed HB,Idriss IM.Simpli f ed procedure for evaluating soil liquefaction potential. Journal of Soil Mechanics and Foundations Division,ASCE 1971;97(9):1249-73. Seed HB.Soil liquefaction and cyclic mobility evaluation for level ground during earthquakes.Journal of Geotechnical Engineering Division,ASCE 1979;105(2): 201-55.

Wang G,Zhang J,Wei X.Seismic response analysis of a subway station in lique f able soil.Chinese Journal of Geotechnical Engineering 2011;33(10):1623-7(in Chinese).

針對(duì)傳統(tǒng)JSP，文獻(xiàn)[4-5]分別針對(duì)N6、N7鄰域結(jié)構(gòu)，提出了保證可行解的工序移動(dòng)條件。文獻(xiàn)[25]對(duì)文獻(xiàn)[5]中工序移動(dòng)條件進(jìn)行了擴(kuò)展，取消了關(guān)鍵工序條件限制。結(jié)合FJSP的特點(diǎn)，文獻(xiàn)[21]對(duì)文獻(xiàn)[25]中定理的適用范圍擴(kuò)展應(yīng)用到了FJSP，本文采用該方法實(shí)現(xiàn)鄰域搜索時(shí)對(duì)可行解的保障技術(shù)。

Wang G,Zhang J.Recent advances in seismic liquefaction research.Advances in Mechanics 2007;37(4):575-89(in Chinese).

Yang Y,Liu X,Liu Q,Chen N.Study on the method for evaluating sand liquefaction potential.Chinese Journal of Hydraulic Engineering 2010;41(9):1061-8(in Chinese).

Zhang J,Wang G.Large post-liquefaction deformation of sand,part I:physical mechanism,constitutive description and numerical algorithm.Acta Geotechnica 2012;7(2):69-113.

Dr.Gang Wangis working as a professor in School of Civil Engineering at Chongqing University,China.He worked as a senior engineer and deputy chief engineer in the Yalong River Hydropower Development Company(2005-2014). His research interests cover constitutive modeling of soils, geotechnical earthquake engineering,dam engineering, numerical methods in geotechnical engineering,etc.

*Corresponding author.Tel.:+86 13808216151.

E-mail address:cewanggang@163.com(G.Wang).

Peer review under responsibility of Institute of Rock and Soil Mechanics,Chinese Academy of Sciences.

1674-7755?2015 Institute of Rock and Soil Mechanics,Chinese Academy of Sciences.Production and hosting by Elsevier B.V.All rights reserved.

http://dx.doi.org/10.1016/j.jrmge.2015.02.005