依兰矿区钻探施工泥浆选型的研究     

魏臣 《中国煤田地质》2007,19(2):72-74

依兰矿区第三系上部的砂泥岩段,因泥岩的水敏水化作用及粗砂岩易坍塌等原因造成,区内钻孔孔壁极不稳定,经常发生粘卡钻具事故。为抑制泥岩的水敏水化,阻止泥岩水化和井壁岩石剥落,增强其防塌能力,在选择腐植酸钾做主剂的基础上选择CMC作降失水增粘剂,选择分子量为300万～500万、水解度30%的聚丙烯酰胺(PAM)作絮凝剂,以加速岩屑沉降,控制固相侵入,降低失水。在钻遇半胶结泥岩时,为防止缩径、坍塌,采用在泥浆中加入重晶石粉,把泥浆比重调整到1.15～1.20g/cm~3,利用泥浆液柱压力控制泥岩缩径和孔壁坍塌。通过实验及现场应用,为该区选择的KHM-CMC-PAM高聚物泥浆配方,能有效地防止水敏性易塌地层的粘卡钻事故,具有护壁防塌、提高钻效等技术效果。  相似文献   

金伯利岩中“熔离小球”的特征及其成因     

路凤香  张宏福  陈美华  郑建平  尹作为  任迎新  赵崇贺  叶德隆 《现代地质》2007,21(2):241-246

在金伯利岩人工重砂中发现的“熔离小球”,直径多数<1 mm,除个别出现微晶外,均为非晶质,属于熔体淬火冷却产物。提供了29个小球的主元素分析和3件微量元素分析结果。“熔离小球”按成分可分为3种类型:(1)高铁钛小球;(2)硫铁镍小球;(3)浅色硅铝质小球。其中高铁小球w(FeO)高达99.39%,高钛小球w(TiO2)达45.90%,它们含MnO也偏高,最高达23.75%。Fe、Mn、Ti都属于高负电性元素,在熔体中与氧结合的键强度大,容易发生熔离。硫铁镍小球的w(SO3)变化于38.27%~51.95%,w(FeO)为0.31%~23.10%,w(NiO)为25.24%~61.05%。浅色小球w(SiO2)变化范围为24.01%~52.64%,Al2O3、CaO含量高但变化范围大,总体成分接近基性—超基性硅酸盐熔浆。主元素、微量元素特征以及硫铁镍小球中发现了高镁(Fo=0.95)橄榄石捕虏晶表明,小球形成于金伯利岩岩浆的介质环境。此外高铁及硅铝质两种成分呈交生结构的两相小球的发现,暗示二者为熔离作用成因。小球的熔离作用可以应用SiO2-FeS-FeO的液态不混溶相图做出解释。认为小球形成于岩浆结晶的晚期阶段,相对富含CO2、SO3、FeO、MnO、TiO,在岩浆快速上升、快速降温、降压、熔体中出现了多种局部有序区的条件下发生的。  相似文献   

湛江海湾大桥塔上锚管定位方法介绍     

李毛毛  刘成龙 《四川测绘》2007,30(2):92-96

斜拉桥是一个受力结构复杂、各构件间相互影响较大的超静定结构体,斜拉索锚管的安装定位是其施工的重点与难点之一。本文结合湛江海湾大桥工程实践,介绍一种涉及到大跨度斜拉桥主塔锚管安装定位的原理、放样数据计算的理论、现场安装测量控制和精度等内容的新方法。  相似文献   

Mineralogical studies of pyropes in kimberlites from China     

董振信 《中国地球化学学报》1998,17(1):29-43

Based on the measurements of refractive index,specific gravity,unit cell parameter,and mineral chemistry and infrared absorption spectrum analyses of pyropes in kimberlites from China,systematic studies of the Physical properties and compositional variations of pyropes of different colors and diverse paragenetic types,within and between kimberlite provinces have been undertaken,The origin of pyropes in the Kimberlites and the depth of their formation have been discussed.Pyropes of the purple series are different from those of the orange series in physical and chemical properties,for exaple,pyropes of the puple series are higher in α0,RI,SG,Cr2O3,MgO,Cr/(Cr Al),Mg/(Mg Fe),and Mg/(Mg Ca),and lower in Al2O3,Fe2O3 FeO than those of the orange series.The classification of garnets in kimberlites from china by the Dawson and Stephens‘ method(1975) has been undertaken and clearly demonstrates that pyropes of diamond-rich kimberlites contain much more groups than those of diamond-poor,especially diamond-free kimberlites.The higher in α0,RI,SG,Cr2O(3.Cr/(Cr Al),knorringite and Cr-component the pyropes are ,the richer in diamond the kimberlites will be.The infrared absorption spectrum patterns of pyropes change with their chemical composition regularly,as reflected in the shape and position of infrared absorption peaks.Two absortpion bands at 862-901 cm^-1 will grade into degeneration from splitting and the absorption band positions of pyropes shift toward lower frequency with increasing Cr2O3 content and Cr/(Cr Al) ratio of pyropes,LREE contents of orange pyrope megacrysts are similar to those of porple pyrope macrocrysts,but the former is higher in HREE than the latter,showing their different chondrite-normalized patterns.The formation pressures of pyropes calculated by Cr-component,Ca-component,knorringite molecules of pyropes show that some pyropes of the purple series in diamondiferous kimberlites fall into the diamond stability field.but all pyropes of diamond-free kimberlites lie outside the diamond stability field.The megacrysts were formed through early crystallization of kimberlites magma at high pressure condition,the majority of the purple pyrope macrocrysts have been derived from disaggregated xenoliths but the minoirty of them appear to be fragments of the discrete megacryst pyropes,or phenocrysts.  相似文献   

Damage distribution during the 1994 Northridge, California, earthquake relative to generalized categories of surficial geology     

M.D. Trifunac  M.I. Todorovska 《Soil Dynamics and Earthquake Engineering》1998,17(4):239-253

The spatial distributions of severely damaged buildings (red-tagged) and of breaks in the water distribution system following the 1994 Northridge, California, earthquake (M_L = 6·4) are investigated relative to the local characteristics of surficial geology. The pipe breaks are used as an indicator of nonlinear soil response, and the red-tagged buildings as indicator of severe shaking. The surficial geology is described by several generalized categories based on age, textural character and thickness of the near surface layer. Two regions are studied: the San Fernando Valley and Los Angeles-Santa Monica. The analysis shows that there is no simple correlation between damage patterns and surficial geology. Single family wood-frame buildings were damaged less when built on fine silt and clay (0–3 m thick) from the late Holocene.  相似文献   

Experimental and computational validation and verification of the Stokes–Darcy and continuum pipe flow models for karst aquifers with dual porosity structure     

Xiaolong Hu  Xiaoming Wang  Max Gunzburger  Fei Hua  Yanzhao Cao 《水文研究》2012,26(13):2031-2040

In our previous study, we developed the Stokes–Darcy (SD) model was developed for flow in a karst aquifer with a conduit bedded in matrix, and the Beavers–Joseph (BJ) condition was used to describe the matrix–conduit interface. We also studied the mathematical well‐posedness of a coupled continuum pipe flow (CCPF) model as well as convergence rates of its finite element approximation. In this study, to compare the SD model with the CCPF model, we used numerical analyses to validate finite element discretisation methods for the two models. Using computational experiments, simulation codes implementing the finite element discretisations are then verified. Further model validation studies are based on the results of laboratory experiments. Comparing the results of computer simulations and experiments, we concluded that the SD model with the Beavers–Joseph interface condition is a valid model for conduit–matrix systems. On the other hand, the CCPF model with the value of the exchange parameter chosen within the range suggested in the literature perhaps does not result in good agreement with experimental observations. We then examined the sensitivity of the CCPF model with respect to the exchange parameter, concluding that, as has previously been noted, the model is highly sensitive for small values of the exchange parameter. However, for larger values, the model becomes less sensitive and, more important, also produces results that are in better agreement with experimental observations. This suggests that the CCPF model may also produce accurate simulation results, if one chooses larger values of the exchange parameter than those suggested in the literature. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Exploring the X-ray spectral variability of MCG–6-30-15 with XMM–Newton     

J. Larsson  A. C. Fabian  G. Miniutti  R. R. Ross 《Monthly notices of the Royal Astronomical Society》2007,376(1):348-352

We present a study of the spectral variability of the Seyfert I galaxy MCG–6-30-15 based on the two long XMM–Newton observations from 2000 and 2001. The X–ray spectrum and variability properties of the 2001 data have previously been well described with a two-component model consisting of a variable power-law and a much less variable reflection component, containing a broad relativistic iron line from the accretion disc around a rapidly rotating Kerr black hole. The lack of variability of the reflection component has been interpreted as an effect of strong gravitational light bending very close to the central black hole. Using an improved reflection model, we fit the two-component model to time-resolved spectra of both observations. Assuming that the photon index of the power law is constant, we reconfirm the old result and show that this does not depend on the time-scale of the analysis.  相似文献   

基于Web的地下管网溯源分析算法研究     

董万虎 《地理空间信息》2021,19(4):71-72,77

利用.NetCore的并行运算机制,实现基于Web的高性能地下管网的溯源分析功能。实践证明当某点管网数据监测出现异常时,能够快速分析所有可能流经该点源头管网信息,并在地图上动态展示分析结果,达到快速定位查询管网源头的区域管理目的。  相似文献   

超长管棚施工技术在山岭隧道软弱围岩中的应用          下载免费PDF全文

冯劲  林廷松  周红升 《探矿工程》2010,37(11):73-75

以黄衢南高速公路阳排尖隧道为例,介绍了大于30 m超长管棚施工技术;并根据现场监控量测数据,对左右洞不同管棚施工技术效果进行对比分析;分析结果显示,一次性施作超长管棚在山岭隧道软弱围岩地段有较好的实用性。  相似文献   

苏通大桥二期试桩后压浆的施工及效果检测          下载免费PDF全文

徐家明  李兆琴  方宏 《江苏地质》2010,34(1):79-83

随着高层建筑和大型桥梁的兴建,钻孔灌注桩在工程中已得到了极为广泛的应用。但是,钻孔灌注桩的固有缺陷,例如孔底沉渣、孔壁泥浆、端阻力、侧阻力发挥不同步等,限制了其承载力的发挥并且沉降较大。由此,钻孔灌注桩压力注浆技术应运而生,并被逐渐应用于工程实践中。所以,对桩的后压浆施工工艺、受力机理等技术问题进行研究是非常重要的。在国内外现有的理论研究和工程应用基础上,通过对苏通大桥Ⅱ期的试桩工程施工,详细阐述了桩端后压浆技术的具体应用。同时,利用钻孔取心及CT检测技术分析后压浆的施工效果。  相似文献