地震工程学报
地震工程學報
지진공정학보
China Earthquake Engineering Journal
2015年
1期
34-39
,共6页
罗会武%彭旭%陈生水%刘恩龙
囉會武%彭旭%陳生水%劉恩龍
라회무%팽욱%진생수%류은룡
掺细料砾石土%动孔压%动三轴试验%动力特性
摻細料礫石土%動孔壓%動三軸試驗%動力特性
참세료력석토%동공압%동삼축시험%동력특성
gravels mixed with fine grains%dynamic pore pressure%dynamic triaxial test%dynam-ic properties
地震荷载作用下发生滑坡的滑动带通常由粗颗粒与细颗粒组成。滑带土的动力性质及动孔隙水压力的发展对边坡的稳定性至关重要。对掺细料砾石混合土进行动三轴试验来探讨细料(粒径小于0.5 mm)含量对砾石(粒径6~20 mm)混合土的动孔压特性的影响,进行细料含量为0%、20%和40%的三组试样的动三轴试验,采用固结围压为100 kPa、固结应力比为1.0、频率为1.0 Hz,施加轴向动应力分别为0.50、0.55、0.60和0.65 kN,得到动孔压的变化规律。试验发现:(1)相同激振力作用下,随着细料含量的增加,动孔隙水压力增长速度逐渐变缓;相同细料含量时,随着激振力的增大,动孔隙水压力增长速度变快。(2)激振力较大和细料含量较少时,动孔隙水压力在较少的振次下达到较大值并趋于稳定。(3)细料含量为20%的砾石混合土试样在试验终止时的振动次数最大,细料含量为40%的砾石混合土在试验终止时的振动次数最小。(4)当细粒含量为0%和20%时,试验终止时最终的孔压都可以接近固结围压;当细粒含量为40%,激振力较大时,试验终止时最终的孔压才接近固结围压,而激振力较小时最终的孔压远远没有达到固结围压。
地震荷載作用下髮生滑坡的滑動帶通常由粗顆粒與細顆粒組成。滑帶土的動力性質及動孔隙水壓力的髮展對邊坡的穩定性至關重要。對摻細料礫石混閤土進行動三軸試驗來探討細料(粒徑小于0.5 mm)含量對礫石(粒徑6~20 mm)混閤土的動孔壓特性的影響,進行細料含量為0%、20%和40%的三組試樣的動三軸試驗,採用固結圍壓為100 kPa、固結應力比為1.0、頻率為1.0 Hz,施加軸嚮動應力分彆為0.50、0.55、0.60和0.65 kN,得到動孔壓的變化規律。試驗髮現:(1)相同激振力作用下,隨著細料含量的增加,動孔隙水壓力增長速度逐漸變緩;相同細料含量時,隨著激振力的增大,動孔隙水壓力增長速度變快。(2)激振力較大和細料含量較少時,動孔隙水壓力在較少的振次下達到較大值併趨于穩定。(3)細料含量為20%的礫石混閤土試樣在試驗終止時的振動次數最大,細料含量為40%的礫石混閤土在試驗終止時的振動次數最小。(4)噹細粒含量為0%和20%時,試驗終止時最終的孔壓都可以接近固結圍壓;噹細粒含量為40%,激振力較大時,試驗終止時最終的孔壓纔接近固結圍壓,而激振力較小時最終的孔壓遠遠沒有達到固結圍壓。
지진하재작용하발생활파적활동대통상유조과립여세과립조성。활대토적동력성질급동공극수압력적발전대변파적은정성지관중요。대참세료력석혼합토진행동삼축시험래탐토세료(립경소우0.5 mm)함량대력석(립경6~20 mm)혼합토적동공압특성적영향,진행세료함량위0%、20%화40%적삼조시양적동삼축시험,채용고결위압위100 kPa、고결응력비위1.0、빈솔위1.0 Hz,시가축향동응력분별위0.50、0.55、0.60화0.65 kN,득도동공압적변화규률。시험발현:(1)상동격진력작용하,수착세료함량적증가,동공극수압력증장속도축점변완;상동세료함량시,수착격진력적증대,동공극수압력증장속도변쾌。(2)격진력교대화세료함량교소시,동공극수압력재교소적진차하체도교대치병추우은정。(3)세료함량위20%적력석혼합토시양재시험종지시적진동차수최대,세료함량위40%적력석혼합토재시험종지시적진동차수최소。(4)당세립함량위0%화20%시,시험종지시최종적공압도가이접근고결위압;당세립함량위40%,격진력교대시,시험종지시최종적공압재접근고결위압,이격진력교소시최종적공압원원몰유체도고결위압。
Under seismic loading,sliding bands originating from landslides are usually composed of coarse and fine grains.The dynamic features of sliding-band soils and the development of dy-namic pore water pressure during the cyclic loading process are extremely important to the stabil-ity of slopes.Dynamically cyclic triaxial tests on gravels including fine particles smaller than 0.5 mm were conducted to investigate the influence of fine particles on the dynamic pore water pres-sure features of these mixed soil gravels of 6~20 mm.Three groups of specimens with fine con-tents of 0%,20%,and 40% were tested using a triaxial dynamic apparatus wherein the consolida-tion confining pressure was 100 kPa,the ratio of consolidation was 1.0,and the frequency was 1.0 Hz.Dynamic axially cyclic stress of 0.50 kN,0.55 kN,0.60 kN,and 0.65 kN was applied to each group.The specimen shape was cylindrical,and the specimen size was 100 mm × 200 mm.The dry densities of the specimens with fine contents of 0%,20%,and 40% were 1.605 g/cm3 ;1.741 g/cm3 ,and 1.570 g/cm3 ,respectively.After the tests were concluded,the development of dynamic pore water pressure and its evolution laws were obtained and analyzed in detail.It was experimen-tally determined that under the same dynamic load,a more rapid increase in dynamic pore water pressure occurs when the fine soil particle content is small;when the content is high,the speed is lower.For the same fine grain content,a small dynamic load resulted in a low speed increase of dy-namic pore water pressure;when the dynamic load was high,the increase was rapid.Moreover,a larger dynamic load and smaller fine grain content resulted in relatively larger dynamic pore water pressure of soil specimens that tended to be stable.The number of the dynamic cycles was largest (smallest)when the specimen with fine content of 20% (40%)was wreck.At the end of the ex-periment,the pore water pressure of the soil specimen was close to the consolidation confining pressure with fine contents of 0% and 20%.For the specimens of 40% fine content,the pore water pressure was close to the consolidation confining pressure under a high dynamic load.