电感应变片

本文介绍发明专利产品--电感应变片的基本原理、性能特点和应用情况。     

Experimental test of the calcite strain gage technique at low confining pressure

A series of experiments were conducted on Indiana limestone to test the applicability of calcite strain gage technique to deformations at low confining pressures. Experiments were conducted dry, at 13.8 MPa (138 bars, 2000 psi) confining pressure. These experiments indicate that both the least squares strain gage technique and the numerical dynamic analysis (NDA) technique locate the principal strain axes to within 5.0 degrees. Strains calculated by the least squares strain gage technique are accurate at low strains (less than 5%), and increasingly inaccurate at higher strains. At low strains, the calculated strain reflects the maximum strain (including elastic strain) experienced by the core. At higher strains, the increasing inaccuracy of calculated strain was accompanied by increasing negative expected values. In these experiments, microcracking played a significant part in deformation and effected twinning in calcite, and therefore the recorded strain.     

Development of Soil Strain Gage Instrumentation

A brief review of the errors from mechanical mismatch of ‘Spool Gage’ commonly used in field soil strain measurement is made. The behavior of a unique contactless magnetic coil gage is analyzed, which is relatively free from mechanical mismatch effects. The structure and main specifications of the instrument designed for the measurements of both static and dynamic strain in soil are presented here.     

土壤应变测试仪的研制

本文简要地评估了土力学现场测量中常用的连杆式应变传感器的力学匹配误差。对一种特殊的,匹配误差小的非接触互感式传感器的特性作出分析。设计了与这种传感器配用的,适合于动、静态测量的土壤应变仪,给出了它的主要性能指标。     

地质力学模型试验中软弱结构面内埋式位移系统的研制与应用

在高拱坝坝肩稳定地质力学模型试验研究过程中,坝肩岩体内各软弱结构面的相对位移变化趋势是判定坝肩失稳及分析坝肩整体稳定安全度的重要参考依据。目前的量测仪器,如电阻应变片、表面位移计只能对坝体应变和坝肩抗力体表面位移进行量测,而对于坝肩岩体内软弱结构面的相对位移则难以获取。因此,针对上述问题,以电阻应变技术为基础,研制了用于获取结构面相对位移的内埋式位移系统,该系统由信号采集仪器、惠斯通电桥和位移传感器组成。在模型试验中,通过内埋式位移系统,获得加载过程中相应测点的应变变化过程,再由应变-位移关系曲线,即可得出位移值。结合锦屏一级高拱坝整体稳定地质力学模型试验,将该系统安装于需量测的坝肩软弱结构面上,获得了结构面在加载过程中的位移变化过程线,同时与大坝应变和坝肩表面位移监测成果进行对比分析,验证了内埋式位移系统的可行性,其测试成果可为判定坝与地基的整体稳定提供依据。     

砂土中抗拔桩与抗压桩模型试验研究

为研究单桩在抗拔与抗压条件下承载能力、桩身轴力以及侧摩阻力分布规律的不同,进行了砂土中长径比大于40的抗拔桩与抗压桩室内模型试验,通过桩身内设置电阻应变片,测得各级荷载下桩身不同深度的应变。分析表明,抗拔桩不论是位移还是位移增长速率,都远远超过抗压桩。因此,抗拔桩设计时应综合考虑桩顶上拔量来确定抗拔承载力。抗拔桩与抗压桩的桩身轴力分布具有相似的特性,试验所得抗拔总侧摩阻力折减系数?=0.56。抗拔桩与抗压桩侧摩阻力都是从上部开始发挥并向下传递,随着荷载的增加,上部侧摩阻力变化很小,桩身中下部侧摩阻力迅速增长。抗拔桩桩端部侧摩阻力表现出弱化效应,抗压桩则表现出强化效应。     

A piezometer for Stress Wave Measurement in Rock Mass

A new type of stress piezometer, RS stress gage, is presented in this paper. This new type of stress gage make use of piezoelectricity of piezocrystal to measure dynamic stress and read the magnitude directly. To avoid the bad matching of the gage and rock mass in situ, the shell of the gage is made of rock core from in situ. It has been proved that the new stress gage can work well during the measuring of the stress of blast wave in rock mass as long as it was made fine, calibrated accurately, and inserted carefully.     

测量岩体应力波的压电应力计

本文介绍一种用于岩体爆炸测量的新型压电应力计--RS 型应力计.它利用压电晶体的压电效应直接测量应力。由于外壳采用爆炸现场测点处的岩芯材料制成,避开了应力测量中难以解决的匹配问题.实践表明:只要保证 RS 型应力计按规定工艺要求制作,并进行系统的标定和回填,对中硬和坚硬岩体中自由场和毛洞周边的爆炸应力测量是可行的。     

In-Situ strain measurement by photoelastic bar gages, 1. The method

A technique is described for measuring recoverable strain in situ using bridged photoelastic bar gages and a simple reflecting polariscope. Rosettes of 0.2 × 0.4 × 4-cm bars are bonded to the rock for 0.6 cm at each end. Change in strain is measured following overcoring with a 10-cm bit. Correction for strains in the order of 30 · 10^?6/°C, due to differential thermal expansion between rock and gage, are made by monitoring dummy gages mounted on free blocks. Bar gages have been satisfactorily tested against foil resistance gages. Rosettes mounted closely adjacent on a free granite block showed a reasonable homogeneity of response.     

3D-DIC系统在岩石力学试验中的应用

介绍了全场3D-DIC系统,在试样周围均匀布置三组3D采集元,利用散斑图像的采集,尽可能在较大范围内捕捉试样表面的变形并进行分析。为了验证3D-DIC系统测量结果的可靠性,以江持安山岩为试验材料,进行了单轴压缩条件下的恒定应变速率和交替应变速率试验。通过3D-DIC系统的测量结果与应变片测量结果的对比发现,两者吻合度较好,表明3D-DIC系统能够满足岩石力学试验非接触式、可视化变形测量的需求。另外以田下凝灰岩为试验材料,通过图像分析得到了加载过程中岩石表面的全场变形信息,发现岩石变形的不均匀性和应变局部化现象,表明利用3D-DIC系统对岩石破裂过程变形测量比传统变形测量方法更具有优越性,为岩石力学试验研究提供了一种新的、便捷的测试方法。     

特殊保径结构PDC钻头在渤海油田应用

随着石油勘探开发技术的不断进步,旋转导向钻井系统在现代钻井中的应用越来越多。但当面临更加复杂及曲率更高的井身结构时,单依靠Xceed指向式旋转导向工具不能完全满足钻井作业的要求。针对这一情况,提出一种特殊保径结构的PDC钻头,其特殊在于上部1 in标准保径,下部3 in保径为0.6°倒角保径。经过计算机模拟分析,这种PDC钻头相较于常规PDC钻头不但可以提高钻具组合的造斜能力还能提高钻具工作稳定性。在渤海油田现场使用表明,这种特殊保径结构的PDC钻头具有更强的造斜能力,保证旋转导向工具和其它井下工具稳定性,减缓井下仪器由于井下震动导致的失效。     

地面积雪测量与雨量器量测降雪量一致性实验研究

1989年10月至1990年5月间的8个降水时段的对比测量表明,乌鲁木齐河源高山区空冰斗小流域内雨量器冬季测量的降雪量约为地面积雪测量所得实际降雪量的73%,二者的测量结果不具有一致性,因此,雨量器的测量值不能代表地面实际降雪量.在流域水量平衡和融雪径流计算中,必须首先修正降雪量测量的系统误差.     

Comparing the Response of Static Loading Tests on Two Model Pile Groups in Soft Clay

Static load test program was performed on a single pile and two 16-pile groups with equal and different pile lengths. The soil profile consists of sand fill to 0.5 m depth placed on a thick deposit of soft, normally consolidated and compressible clay. The closed end steel pipe piles in 60 mm diameter were installed from 1.5 m through 2.1 m depth within soft clay deposit. The center-to-center distance of piles in group is about 3 times of pile diameter. The strain gages were installed at one level above and two through four levels below ground surface. Tests were carried out about 7 days after driving by method of a series of load increments placed every 5-min until plunging failure occurred. The load at plunging failure for the single pile, the equal-length pile group and the different-length pile group were about 3, 40 and 48 kN, respectively. The movements at start of failure were about 12, 18, and 17 mm, respectively. The analysis of strain gage measurements indicates that the load distribution on piles in the different-length pile group has become significantly uniform.     

Development and Application of PPT-type Static-dynamic Pore Pressure Transducer Gage

PPT-type static-dynamic pore pressure transducer gage is developed and designed by our institute. The principle, technical behavior, calibration method, and application to practical engineering are presented in this paper.     

PPT型动静孔隙水压力传感器的研制及其应用

本文介绍了我所自行设计研制的PPT系列动静态孔隙水压力传感器的原理、技术性能、标定方法及其在工程实践中的应用等情况。     

Assessment of satellite-based rainfall estimates in urban areas in different geographic and climatic regions

This paper presents an assessment of the 3B42 research version rainfall product from NASA’s Tropical Rainfall Measuring Mission Multi-satellite Precipitation Analysis (TMPA). The study provides new results of TMPA data accuracy in urban areas and highlights trends associated with the climatological indicators of temperature and relative humidity in cities. Ten years (1998-2007) of TMPA data were analyzed for three case study cities in the United States (Houston, Atlanta, and Las Vegas) and one in Korea (Cheongju), representing semi-arid to humid climates. At each location, an urbanized river basin and non-urbanized river basin were selected and comparisons between TMPA and rain gage observations were made for recorded storm events in the study period, the largest storm events by total depth, and selected hurricanes and topical storms. The results indicate TMPA data match well with rain gage observations at all locations. TMPA is slightly underestimated for semi-arid regions and overestimated for humid regions. The relative magnitude of TMPA rain event accumulation compared to rain gage accumulation is noted to be smaller for urbanized watersheds and high intensity events. The correlation of TMPA accuracy with temperature and relative humidity and the analysis of accuracy by season indicate TMPA is more accurate for convective rainfall events. This suggests a possible linkage between the observed urban-modified temperatures, hypothesized enhanced convection, and improved TMPA accuracy in urban areas.     

地浸砂岩型铀矿卵砾石层钻进用钻头的试验研究

介绍了金刚石-硬质合金复合球齿钻头在内蒙古某地区铀矿床卵砾石层中的生产试验情况.在钻进卵砾石层时,保径未做加强的金刚石-硬质合金复合球齿钻头的平均钻进效率为2.50 m/h,钻头的平均寿命为7.34 m/个;保径加强型金刚石-硬质合金复合球齿钻头的平均钻进效率为2.82 m/h,钻头的平均寿命为10.18 m/个;而普通合金钻头的平均钻进效率为1.29 m/h,钻头的平均寿命为1.19 m/个.试验表明金刚石-硬质合金复合球齿钻头是一种理想的钻进卵砾石层的钻头.     

适用于检测冻土的超声波测试系统的设计与研制

超声波波速测试作为一种无损检测已经广泛应用到岩土工程行业,该测试方法也是获得岩土体物理力学参数的有效方法.目前鲜有关于冻土的声波测试的技术和方法的报导,已有的冻土声波测试都是在垂直方向上忽略换能器的质量并在常温下快速测试声波通过时间,难以满足测试精度.鉴此,在购置常温声波测试主机的基础上,充分考虑冻土对温度敏感的特性、换能器在水平方向的测试以及土样与换能器之间的耦合程度,设计了一种适用于多种类型的冻土超声波换能器支架和恒温箱的测试系统,恒温箱意在提供适合不同温度下土体的测试环境（-30℃～+30℃）,换能器支架可供低温、提供多种尺寸冻土试样的横波和纵波的测试平台.为避免垂直测试中换能器和土样自身对测试的影响,除了支架提供水平测试平台外,在调节换能器与土样接触距离的螺杆顶端放置应变片测试冻土样与换能器之间的接触程度以提高冻土声波波速的测试精度.利用该测试系统对不同负温下冻土样品进行测试,数据结果证明了该测试系统的实用性和良好的测试精度.     

电镀热压人造金刚石孕镶块嵌齿薄壁钻头的研制

采用低温电镀工艺（室温）产生热压刚石孕镶块钻头,或者说把金刚石孕镶块镶嵌在钻头钢体上,然后在其表面镀覆一层金刚石复合镀层使其与钢体相结合从而使其避免银焊对金刚石的二次热损伤,使这种钻头具有胎体性能可调性好和内外保径强的优点。经探索性试验,取得了较好的效果,受到了用户好评。