黄河流域河流水化学特征初步分析   总被引：7，自引：0，他引：7  

过常龄 《地理研究》1987,6(3):65-73

本文根据黄河流域69个水化学测站500个站年资料分析了水化学特征及其区域分异。  相似文献   

A new technique for non‐destructive field measurement of rock‐surface strength: an application of the Equotip hardness tester to weathering studies     

Hisashi Aoki  Yukinori Matsukura 《地球表面变化过程与地形》2007,32(12):1759-1769

Tafone‐like depressions have developed on the Aoshima sandstone blocks used for a masonry bridge pier in the coastal spray zone. A thin layer of partial granular disintegration was found on the surface in depressions. To evaluate quantitatively the strength of the thin weathered layer, the hardness was measured at the surface of the sandstone blocks using both an Equotip hardness tester and an L‐type Schmidt hammer. Comparison of the two testing results indicates that the Equotip hardness value is more sensitive in evaluating the strength of a thin layer of weathered surface rock than the Schmidt hardness value. By applying two methods, i.e. both the repeated impact method and the single impact method, the Equotip tester can evaluate the strengths of fresh internal and weathered surficial portions of rocks having a thin weathering layer. Comparison of the two strengths enables evaluation of strength reduction due to weathering. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Estimation of rock engineering properties using hardness tests     

Faisal I. Shalabi  Edward J. Cording  Omar H. Al-Hattamleh 《Engineering Geology》2007,90(3-4):138-147

In engineering projects such as tunnels, dams, foundations, and slope stability, the strength and elastic properties of the intact rock affect both the project design and the construction operation. It is sometimes expensive and time consuming to perform direct tests to evaluate the engineering properties (such as strength, modulus of elasticity, and Poisson's ratio) of the intact rock. The purpose of this work is to investigate the relationships between the engineering properties of the intact rock and the different types of hardness (Schmidt, shore scleroscope, abrasion, and total hardness), which are relatively cheap and easy to evaluate. In this study, dolomite, dolomitic limestone, and shale rocks were used. For simplicity, linear statistical analyses were performed. The results show that there are good relationships between the engineering properties of the intact rock and its hardness. Also, the results of this study are compared well with the results obtained by other investigators conducted on different types of rocks.  相似文献   

Some Attempts for Estimating Rock Strength and Rock Mass Classification from Cutting Force and Investigation of Optimum Operation of Tunnel Boring Machines     

K. Fukui  S. Okubo 《Rock Mechanics and Rock Engineering》2006,39(1):25-44

Summary. Tunnel face and wall collapse are common during excavations performed by tunnel boring machines (TBMs) due to the difficulty of correctly identifying the properties of the excavated rock. This identification, however, can be simplified by using the cutting force to estimate rock strength, a method that has already proved quite successful in Japanese tunnel excavations. This paper summarizes knowledge relating to the cutting force obtained through tunnel excavation experience, and the relationship between rock strength and TBM operation is discussed. Although TBM operators rely on intuition to set the cutter head speed appropriately, this decision process represents a logical method of operation that takes advantage of the variable speed capability of the cutter head. Selection of appropriate support methods for the excavated face is also a critical issue in tunnel excavation. This selection process is based on the condition of the rock, which is difficult to determine quickly and accurately during tunnel excavation. The present paper uses the excavation of two tunnels to demonstrate that it is possible to assign rock mass classifications accurately based on rock strength when boring a uniform rock type. It is also shown that the rock mass can be classified from the rock strength normalized by the uniaxial compressive strength when boring through mixed rock types.  相似文献   

Correlation of Schmidt hardness with unconfined compressive strength and Young''s modulus in gypsum from Sivas (Turkey)     

I &#x;k Y&#x;lmaz  Hüseyin Send r 《Engineering Geology》2002,66(3-4):211-219

This study aims to express the relationships between Schmidt rebound number (N) with unconfined compressive strength (UCS) and Young's modulus (E_t) of the gypsum by empirical equations. As known, the Schmidt hammer has been used worldwide as an index test for a quick rock strength and deformability characterisation due to its rapidity and easiness in execution, simplicity, portability, low cost and nondestructiveness. In this study, gypsum samples have been collected from various locations in the Miocene-aged gypsum of Sivas Basin and tested. The tests include the determination of Schmidt hammer rebound number (N), tangent Young's modulus (E_t) and unconfined compressive strength. Finally, obtained parameters were correlated and regression equations were established among Schmidt hammer rebound hardness, tangent Young's modulus and unconfined compressive strength, presenting high coefficients of correlation. It appears that there is a possibility of estimating unconfined compressive strength and Young's modulus of gypsum, from their Schmidt hammer rebound number by using the proposed empirical relationships of UCS=exp(0.818+0.059N) and E_t=exp(1.146+0.054N). However, the equations must be used only for the gypsum with an acceptable accuracy, especially at the preliminary stage of designing a structure. Finally, by using the obtained Schmidt hammer rebound number from this study, unconfined compressive strength was calculated and compared with the calculated value from different empirical equations proposed by different authors. It can be said that it is impossible to obtain only one relation for all types of the rocks.  相似文献   

氮迁移转化对地下水硬度升高的影响   总被引：15，自引：0，他引：15  

王东胜  沈照理 《现代地质》1998,12(3):431-436

城市地下水硬度升高是一个普遍的环境问题,研究表明地下水硬度高值区与硝酸盐污染在空间上的分布具有一致性。通过室内土柱试验和化学热力学模拟,讨论了污水入渗过程中氮迁移转化对水土系统钙镁迁移的影响。结果表明：在连续入渗条件下,阳离子交换作用是控制地下水硬度升高的主要过程;在间歇入渗条件下,硝化作用改变了土水系统的酸碱条件,使钙镁难溶盐溶解,导致地下水硬度升高。  相似文献   

柳州市白云岩区钻孔取芯判断岩体完整性研究     

肖尚惠 《南方国土资源》1998,(1)

建筑岩基的岩体完整性划分是否准确直接影响到建筑物的安全性、施工的可行性及经济性,文章通过钻孔取芯观察岩石破裂面,研究岩质坚硬程度,结合辅助钻进速度、进尺、压力及返水情况,综合判断岩体的完整性,即不要进行统计又无需做测试,具有直观、快速、易行等特点,经２８个工程实例开挖检验吻合率达１００％,准确率高。  相似文献   

Rock hardness and landform development in the Gunong Mulu National Park,Sarawak, E. Malaysia     

Michael J. Day 《地球表面变化过程与地形》1981,6(2):165-172

Rock hardness, measured by the Schmidt Test Hammer, is an important factor in explaining some of the sharp contrasts in relief and wide variety of landforms in The Gunong Mulu National Park. It is also useful in consideration of contemporary geomorphological processes, such as landsliding.  相似文献   

激光硬化技术在强化钻杆接头中的应用     

高科  张祖培  谢晓波  颜恩锋  张海青 《世界地质》2004,23(3):275-278

为了解决钻杆接头在钻进过程中经常拧卸及在加工螺纹时强度降低的问题，采用激光硬化技术来提高钻杆接头的性能。试验结果表明，激光强化钻杆接头表面的硬度、耐磨性及抗疲劳等机械性能都得到提高，同时采用该技术能提高钻杆的使用寿命，且又省工省时。  相似文献   

氮离子注入对钻杆接头材料表面硬度的影响          下载免费PDF全文

刘丽吴东江  庄娟马腾才  田云霞王连元 《探矿工程》2004,31(3):34-35

对钻杆接头材料30CrMnSiA钢的样品进行氮离子注入表面改性试验，结果表明，在不同载荷的情况下，选用氮的注入量为50×1017 N+/cm2是比较合适的，氮离子注入后样品的表面努氏硬度提高1倍多。  相似文献