红粘土桩-网复合地基现场试验研究   总被引：1，自引：1，他引：0       下载免费PDF全文

杨果林  黄向京  赵伟 《水文地质工程地质》2010,37(1):85-89

桩-网复合地基同时具备竖向增强和水平向增强两种加固形式的优点,由桩、网、土三者共同协调作用,有效分担路堤荷载,是一种作用机理复杂的地基加固方法。通过对某客运专线红粘土桩-网复合地基试验段进行的现场测试试验,对复合地基的基底土压力、土工格栅变形、孔隙水压力以及桩土沉降量等方面的测试,得出红粘土复合地基需要在桩、网、桩间土通过一个反复的作用过程才能达到稳定状态等结论,将有助于深入研究桩-网复合地基加固机理,并为进一步完善桩-网复合地基设计方法提供依据。  相似文献   

基于改进的Mohr-Coulomb强度准则下岩石锚杆极限抗拔承载力计算     

贺建清  肖兰  张文勇  高文华 《岩土力学》2016,37(9):2484-2488

岩石锚杆基础作为风电机组基础的一种特殊基础型式,可以充分发挥原状岩体的力学性能,具有良好的抗拔性能。已有研究表明,小而非零拉伸截断改进的Mohr-Coulomb（简称M-C）强度准则更适用于描述岩体的破坏特性。基于小而非零拉伸截断改进的M-C强度准则,建立破坏面上单位面积的能量耗损率表达式。从塑性力学极限分析上限定理出发,构建岩楔体平移破坏机构。根据外部作用荷载和岩楔体自重所做的外功率与沿岩楔体圆破坏锥面的能量耗损率相等的条件,建立虚功率方程,并由此得到了岩石锚杆极限抗拔承载力的计算公式。经原型试验验证,推导公式所得计算值与实测值一致性较好,具有一定的可靠性,且能满足工程实际应用要求。  相似文献   

等效拉压荷载下饱和粉质黏土的弹塑性变形特性研究          下载免费PDF全文

田军  董城  李志勇 《地震工程学报》2016,38(2):292-298

动三轴试验中,若在一定轴向静偏应力基础上施加对称正弦波荷载,土体会在荷载正半部分出现轴向压缩状态,而在荷载负半部分有可能因为侧向应力大于轴向应力而出现轴向等效拉伸状态,将此类荷载暂称为等效拉压荷载。为研究等效拉压荷载下饱和粉质黏土的弹塑性变形,设计了多级正弦波荷载室内不排水动三轴试验。依据试验数据揭示了围压、静偏应力、动偏应力和压实系数对土体弹塑性变形发展的影响,并提出用拉压效应系数来确定轴向塑性累积应变的发展趋势。研究表明:若取轴向压缩方向为正方向,拉压效应系数存在一临界值,当实际值大于临界值时,塑性累积应变向负方向发展,反之则向正方向发展或基本保持不变;同时Hardin模型可以较好地描述饱和粉质黏土的动弹模-动应变关系,且塑性累积应变向负方向发展时动弹模量普遍偏小。  相似文献   

考虑刚度及边界条件的短索索力求解与试验研究   总被引：1，自引：1，他引：0  

石春香  李胡生  林立 《地震工程与工程振动》2010,30(2)

建立了一个非齐次边界拉索力学模型,基于拉索线性振动理论,推导了考虑拉索抗弯刚度及边界条件的拉索频率方程;根据双曲函数的数理特性对频率方程进行了合理简化,得到了实用的频率简化方程,提出了逆过程求解索力的方法和步骤,并探讨了不同支承刚度对索力的影响。设计了室内拉索试验模型并进行了27种工况索力试验,比较了不同工况下的计算索力与实际索力,验证了本文提出的频率简化方程和逆过程求解方法的实用可靠性。  相似文献   

局部断层精确计算定理的证明     

王卫东  包尚联 《CT理论与应用研究》2010,19(4):7-10

本文给出了局部断层图像重建精确计算定理的简单证明。局部断层图像重建是一类仅需较少的扫面数据的断层成像技术,可以有效降低扫面物体的辐射剂量,提高图像重建速度。文献[6]针对局部断层成像的概念提出了一种扇形束的一般扫描轨道的局部断层的精确图像重建方法。本文为文献[6]的定理提供了一个简捷的证明。  相似文献   

Investigations of AGNs by the interplanetary scintillation method     

Vadim S. Artyukh 《Astrophysics and Space Science》2001,278(1-2):185-188

This is a brief review of investigations of AGNs by the interplanetary scintillation method made in Pushchino Radio Astronomy Observatory. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Combined-array images of quasar 3C 286 at 18 cm wavelength     

Fu-jun Zhang 《Chinese Astronomy and Astrophysics》1997,21(4):396-404

MERLIN, VLBI and MERLIN+VLBI images of QSO 3C286 at wave-length 18cm are presented. Low-brightness features in the MERLIN image are just resolved in the MERLIN+VLBI image. But some vestiges still remain. The extension of the central part of the MERLIN+VLBI image is longer than that of the VLBI image. Even though the dynamic range of the MERLIN+VLBI image is better than 1000:1, the counter jet is not found. Several models are used to interpret the observed structures.  相似文献   

Surface Tension Effects of Humic-Like Substances in the Aqueous Extract of Tropospheric Fine Aerosol   总被引：1，自引：0，他引：1  

Gyula?KissEmail author  Etelka?Tombácz  Hans-Christen?Hansson 《Journal of Atmospheric Chemistry》2005,50(3):279-294

Organic aerosol constituents can influence the surface tension of nucleating cloud droplets and thereby modify the critical supersaturation necessary to activate aerosol particles. Model calculations, based on experiments carried out with different surrogates, led to contradictory conclusions on the effect of organic components on activation, indicating that the results depend very much on the surrogate selected. In order to reduce this uncertainty surface tension measurements were performed on real atmospheric aerosol components. Humic-like substances (HULIS) that accounted for 60% of the water-soluble organic carbon present in rural aerosol were isolated from 32 samples covering different seasons. The isolated organic matter present in a concentration of about 1 g L^–1, decreased the surface tension of the aqueous solutions by 25–42% as compared to pure water. This effect was further enhanced when humic-like substances were mixed with ammonium sulphate. In order to support model calculations Szyskowski functions were fitted to the data to formulate the surface tension effect as a function of concentration.Finally, natural humic substances (fulvic and humic acids) were investigated under the same conditions. The experiments revealed that the surface tension decreasing effect of atmospheric humic-like substances differed from that of the studied terrestrial and aquatic humic substances: the latter substances decreased the surface tension of the aqueous solution to a lesser extent (7–23%) than atmospheric HULIS. This deviation can be explained with the different composition (e.g. the ratio of aromatic to aliphatic moieties) of the substances investigated.  相似文献   

Interfacial tension studies between Fe-Cu-Ni sulfide and halo-norilsk basalt slag system     

Jim Mungall 《中国科学D辑(英文版)》2005,48(6):834-839

There are a lot of mafic and ultra-mafic bodies in the earth,but only a few of them include Cu-Ni-PGE deposits.Of interest has been the formation of such deposits as Cu-Ni-PGE sulfide;especially the separa-tion of sulfide liquid from silicate melts.A lot of re-searcher[1—11]have investigated into the tectonic back-ground of Cu-Ni-PGE deposits,the mechanism of the origin and evolution of magma,and the metal element partition coefficient in sulfide liquid and silicate magma.However,the da…  相似文献   

压密注浆技术在涵洞加固中的应用   总被引：1，自引：1，他引：1  

丁海超耿玉岭  王万顺吕莉 《中国煤田地质》2006,18(3):65-67

焦晋高速公路K10＋420涵洞主体建成后，经雨水浸泡，出现严重的不均匀沉降现象。根据钻孔与探井取样资料，设计5排注浆孔进行加固，其中2排沿涵洞内壁两测向涵洞外侧倾斜，斜距分别为2m和4m。加固选用两种注浆参数；即单液浆（0．6：1：0．015）或双液浆（0．6：1：0.3），并根据不同位置采用单液注浆、双液注浆或组合注浆，注浆压力分别为洞内0．8-1．0MPa，洞外0．4-0．6MPa。本次加固工程共施工422个孔，经钻孔取心检验及沉降观测，加固质量满足设计要求。  相似文献