电阻率测深法在陕西富平地区寻找水泥用灰岩的应用

利用电阻率测深法寻找水泥用灰岩,通过对测深数据进行定量反演,确定灰岩的分布范围和覆盖层厚度。     

大口径钻孔下管固管工艺探讨

大口径钻孔的工作管下放和固管工艺直接关系到钻孔的成败。以山西某煤矿瓦斯抽采孔为例,详细阐述了大口径钻孔下工作管和固管的过程,以及保证工程质量和施工安全所采取的防范措施。在施工过程中,钻机根据钻塔的承载力、钻机的提升力实际状况,采用串杠法提吊、水泥浮力塞减轻套管质量、井口密封固管的等施工方法,成功的完成了我国煤炭行业迄今为止下工作管质量、直径最大的大口径钻孔工程,工程质量优良,与采用巨型吊车焊箍直接提吊、井口密封固管的施工方法比较,具有经济效益好,施工场地不受限制等优势。为煤矿瓦斯排放、降温、排水等大口径钻孔工程中的施工提供了一种可靠、经济的施工工艺。     

岩土灌浆技术在滑坡治理中的应用

结合广西壮族自治区桂梧高速公路钟山至马江段百花滩2号滑坡治理的工程实例,介绍了岩土灌浆技术在滑坡治理工程中的具体应用。在了解滑坡成因的基础上,经过科学论证,优选滑坡治理方案。通过灌浆试验研究,得出灌浆的各项设计参数,并将岩土灌浆技术在滑坡治理工程中成功应用,收到了满意的效果。     

RW水泥速凝早强剂在钻探护壁堵漏施工中的应用与研究

针对复杂地层钻进水泥护壁待凝时间长、效果差的问题,通过大量室内试验,进行复合速凝早强剂的配制,作为水泥护壁堵漏外加剂,投入多个矿区不同矿种钻探施工中使用,实现候凝时间短、凝结时间可控、效果好,经济效益和社会效益明显。     

安溪黄厝坪铁矿区复杂地层钻孔护壁堵漏实践

福建省安溪县黄厝坪铁矿区地层复杂,设计钻孔2个。01孔钻探中遇多孔段漏失,反复采用多种堵漏方法顺利终孔,但严重影响了钻探效率。经过总结经验和教训,在02孔施工中,对护壁堵漏措施进行了完善,较好地解决了钻进漏失问题,取得了良好的效果。介绍了2个钻孔的护壁堵漏过程,总结了在破碎漏失严重地层的堵漏对策以及堵漏方法的选择经验。     

一种短基线硐体应变仪

实验发现,在硐体完整基岩1 m深处,日温度波动只有硐体空气中日温度波动的的百分之一左右.将1m基线的硐体应变仪,用自应力水泥耦合在硐体1 m深度的基岩槽中,可以提高硐体应变仪的稳定性和高频性能.     

Leaching evaluation of cement stabilisation / solidification treated kaolin clay

Sustainable land management often requires redevelopment of existing and often contaminated Brownfield sites over use of Greenfield or agricultural land. Stabilisation / solidification (S/S) offer a viable remediation option with particular suitability in treating heavy metal contaminants. However, uncertainties over long-term durability and previously cheap landfill disposal costs resulted in limited use in many countries. There is a need to characterise treated material and assess components containment and release, to improve S/S confidence and inform remedial design, using the evaluation of the leaching controlling mechanisms. To improve understanding of key features that will enable improvements to such designs, this paper presents an evaluation of leaching for CEM II stabilised kaolin, using the leaching behaviour of 4 main components—aluminium, silicon, calcium and sulphur. Results show no detrimental implications on chemical durability due to kaolin degradation with hydration under induced alkalinity, with increased formation of stable cementitious minerals. Availabilities for components show that aluminium and silicon had minimal leachability compared to total content, whilst calcium and sulphur show almost total leaching availability. Decreasing calcium and silicon leachability under natural chemical conditions with increased hydration duration supports the increased formation of stable cementitious products with time, using the products of kaolin dissociation.     

An artificial neural network for groutability prediction of permeation grouting with microfine cement grouts

The use of microfine cements in permeation grouting has been growing as a strategy in geotechnical engineering because it usually provides improved groutability (N). One of the major challenges of using microfine cement grouts is the ability to estimate the N within a reasonable level of error. The suitability of traditional groutability prediction formulas, which are mostly based on the grain-size of the soil and the grout, is questionable for semi-nanometer scale grout. This study first investigated the accuracy of the current formulas; we found that the accuracy ranges from 45% to 68%, a level that is not adequate for practical engineering. An alternative approach, based on a Radial Basis Function Neural Network (RBFNN), was developed. RBFNN provides a prediction with a 95.8% accuracy within a short time frame. Several parameters were considered in our proposed network; besides the grain-size of the soil (D₁₀/D₁₅), other important parameters included the void ratio (e), the fines content (FC), the uniformity coefficient (C_u), the coefficient of gradation (C_z) and the water-to-cement ratio (w/c). A total of 240 in situ data samples were collected to support the training and testing of the network. After finding a good correlation between the field observation and the RBFNN output, it was concluded that RBFNN is a suitable and reliable tool to predict the outcome of permeation grouting when microfine cement grout is used.     

Mix design and expansion behavior of sulpho-aluminate expansive cementitious composite

Sulpho-aluminate expansive cementitious composite is proved to be one of the most effective ways to prevent concrete cracking too soon． Mix design of sulpho-aluminate expansive cementitious composite complete- ly depends on experience and experiments at present． This method ignores the influence of expansion behavior which hinders the application of sulpho-aluminate expansive cementitious composite． The workability,free ex- pansion property,flexural strength and compressive strength of sulpho-aluminate expansive cementitious com- posite have been investigated by tests． The relationship between expansion ratio and mix design parameters such as curing age,water-cement ratio and cement abundance coefficient is deduced according to the experimental statistics． A new simplified approach to mix design of sulpho-aluminate expansive cementitious composite is pro- posed as a reference for construction application,which avoids experiments and experience．     

Spatial Variations of Single-Family Residential Water Consumption in Portland,Oregon

Although water demand theories identify price structures, technology, and individual behavior as determinants of water demand, limited theoretical or empirical evidence suggests a link between urban development patterns and water use. To assess the role of urban development patterns on water demand, we used GIS and statistical models to analyze single-family residential water consumption in the Portland, Oregon, metropolitan area. Our results show that residential water consumption per household at the census block group scale is best explained by average building size, followed by building density and building age, with low water consumption areas clustering together and typically located in high-density and older neighborhoods. Accounting for spatial dependence among residuals, explanatory variables explain up to 87% of variations in water consumption. Our results help to develop a water demand framework that incorporates existing factors with urban development policies to more effectively manage limited water and land resources.