煤层气井注入压降测试井下关井实际应用及存在问题探讨

井下关井是煤层气注入压降试井的重要环节之一，井下关井工具的合理使用，是确保高质量试井成果的前提，针对不同的地层条件及施工情况使用不同种类的关井工具并辅以正确的操作方法，能有效降低试井的风险性，提高试井的成功率并获得高质量，高精度的试井曲线。     

Monitoring artificially stimulated fluid movement in the Cretaceous Dakota aquifer,western Kansas

Aquifer properties can be evaluated by monitoring artificially stimulated fluid movements between wells, if the fluid is heated. Changes in the temperature profile recorded in observation wells indicate the flow path of the heated fluid, which in effect acts as a tracer. A fluid-flow experiment in the Cretaceous Dakota Formation at the Hodgeman County site, west-central Kansas, demonstrated the advantage of using the distributed optical-fiber temperature sensing method for monitoring transient temperature conditions in this hydrological application. The fluid flow in the aquifer was increased by producing water from a pumping well and injecting heated water in an injection well 13 m (43 ft) distant from the pumping well. The time-temperature series data obtained and compared with results from previous pumping tests point to interwell heterogeneity of the aquifer and to a zone in the sandstone aquifer of high hydraulic conductivity. However, the experiment would have allowed further clarification of aquifer heterogeneity and thermal properties if at least one observation well had been present between the injection and production wells. Electronic Publication     

反演瞬态瑞雷波频散曲线映射二维横波速度剖面

由于横波速度与岩土力学参数密切相关,因而是工程地质勘察中的关键参数。基于前人的思想,采用等厚薄层权重自适应迭代阻尼最小二乘法自动反演横波速度,提高横波速度的计算精度,进而映射二维横波速度剖面。用上述方法对某高速公路振冲压碾效果进行了无损检测试验,其结果与钻探和开挖验证一致。     

Load-displacement uncertainty of vertically loaded shallow footings on sands and effects on probabilistic settlement estimation

This article focuses on the statistical characterisation and stochastic modelling of the load-displacement behaviour of shallow footings on cohesionless soils and on the probabilistic estimation of settlement for serviceability limit state design (LSD). The study relies on a field database of 30 full-scale footings subjected to vertical loading with cone penetration testing data available for each site. The performance of three load-displacement models in replicating field data is assessed comparatively through statistical analysis. Load-displacement uncertainty is subsequently modelled probabilistically to perform Monte Carlo Simulation (MCS)-based estimation of footing settlement using the best-performing power law model. The dependence among load-displacement model parameters is investigated and replicated using copula theory. Samples are generated to account for parametric uncertainties in model inputs. The simulation output samples of settlement are examined statistically in order to assess the relevance of parametric and load-displacement uncertainties in settlement estimation, as well as the importance of accounting for correlation between power law model parameters. A simple analytical model for the estimation of settlement at any target reliability level is obtained on the basis of the outputs of MCS. The model can be practically implemented in geotechnical LSD at serviceability limit states.     

利用原位测试数据确定石家庄市天然地基土承载力

原位测试技术具有速度快、费用低、应用广泛的特点。本文利用这一特点，选取静力触探试验和轻便触探试验，采用线性回归分析法建立了比贯入阻力与地基承载力基本值、比贯入阻力与压缩模量、轻型触探指标与地基承载力基本值的相关关系，以便快速、准确地确定石家庄市区地基承载力基本值和标准值。     

An Evaluation of Methods for Assessing the Competence of Laboratories Based on Performance in the GeoPT Proficiency Testing Scheme

The original certification protocol, published by the International Association of Geoanalysts in 2003, specified that the competence of laboratories selected as competent to contribute certification measurements should be evaluated from their performance in the GeoPT proficiency testing programme. Round 39 of the IAG GeoPT proficiency testing programme provided an opportunity to examine four methods of evaluating laboratory competence based largely on the use of proficiency testing z‐scores as performance indicators. This opportunity arose because two test materials were co‐analysed by participating laboratories in this round: a syenite, SyMP‐1, supplied by the USGS, and an established CRM, the nepheline syenite, CGL 006. The performance of laboratories was assessed in four ways; in each case, consensus values and their uncertainties as derived from selective data sets of competent laboratories were compared with results derived from the routine GeoPT data assessment, involving all submitted measurements. An overall comparison of results showed no significant statistical differences in either consensus values or uncertainties between these data sets. This conclusion was unexpected and calls into question the widely held assumption that ‘better’ consensus data would be obtained from a subset of laboratories judged to be competent on the basis of proficiency testing performance indicators.     

瑞利波法检测地基压实度的探讨

在利用瑞利波法测试地基土的压实度时,由于瑞利波速度与压实度之间是一种非线性关系,因此,必须根据瑞利波速度采用非线性反演的方法来获得地基土的压实度。过去一般是采用回归分析的方法,现拟采用人工神经网络的方法,即根据瑞利波速度与神经网络工具反演获得压实度。根据神经网络预测结果与灌砂法测试结果的对比可知,神经网络预测结果的平均绝对误差为1.188 6%,平均相对误差为1.221 4%,其反演结果的精度比回归分析法更高。     

考虑应力路径的地基临塑(界)荷载计算

土的固结不排水剪总应力强度指标在许多地基规范中被建议采用,具有明显的应力路径相关性。推导一个考虑应力路径影响的地基塑性区和临塑(界)荷载计算公式,将此公式和应用室内常规三轴试验指标理论值计算的结果进行了比较,分析了室内常规三轴指标的适用性。     

Bias in the Determination of Zr,Y and Rare Earth Element Concentrations in Selected Silicate Rocks by ICP‐MS when Using Some Routine Acid Dissolution Procedures: Evidence from the GeoPT Proficiency Testing Programme

The analytical results for the modified river sediment, SdAR‐1 circulated in Round 31 of the GeoPT proficiency testing programme, revealed unexpected discrepancies for Zr, Y and most higher atomic number rare earth elements, in determinations made by ICP‐MS using acid attack digestion methods. This investigation compares these ICP‐MS results with those obtained for SdAR‐1 by three other methods: (a) ICP‐MS using fusion/sintering for sample digestion, (b) XRF analysis and (c) INAA. The distribution of results for the elements Rb, Sr, Ce, Y, Yb and Zr is examined and compared with those of the test material for Round 25 of GeoPT, Paraná basalt, HTB‐1. A substantial proportion (though not all) of Y, Yb and Zr determinations in SdAR‐1 by ICP‐MS/acid attack was variably low (sometimes very low) compared with other methods. A detailed evaluation of the procedures used to determine these results indicated that successful determinations by ICP‐MS/acid attack could be made if digestions were made at 180 °C for 48 hr using at least 2 ml HF per 100 mg of sample. We suggest that the more benign conditions (used by many laboratories) resulted in incomplete digestion of resistant minerals, such as zircon.     

注浆锚杆完整性检测方法研究

采用理论分析和实验室测试的方法对锚固锚杆和自由锚杆中的导波传播规律进行了研究,并在频率为20 kHz～ 3 MHz范围内对锚固锚杆和自由锚杆波的传播速度进行了测试,发现锚固锚杆内不同频率的导波传播速度对锚固介质具有不同的敏感性。低频率段（20～200 kHz）的导波传播速度对锚杆锚固质量较为敏感,自由锚杆和锚固锚杆中导波的传播速度相差较大,适合于检测锚杆的锚固质量。高频率段（1～3 MHz）的导波传播速度对锚杆锚固质量不敏感,导波的传播速度基本不变,适合于锚杆完整性检测。探索了利用高频段多频率导波检测锚固锚杆长度的方法。实验室检测结果显示,本检测方法具有很高的精度