穿层爆破在南桐矿瓦斯抽放中的应用与数值模拟     

龚敏  文斌  王德胜 《岩土力学》2012,33(6):1822-1828

穿层抽放是一些高突矿井常用的瓦斯治理手段,在穿层抽放时采用爆破技术已被证明具有良好的抽放效果。以重庆市南桐矿穿层爆破为背景,建立了穿层深孔爆破数学模型;利用数值计算和现场实测抽放数据相结合的方法,分别研究了各爆破孔、控制孔动应力的变化以及爆破应力场强度与抽放效果的关系。研究结果表明,穿层抽放的特点决定了爆破孔与抽放孔的布孔方式。由于炮孔斜穿煤层,煤层各断面动应力场分布极不均匀,药包中心控制孔所受动应力为控制孔中最大。在南桐矿薄煤层试验条件下,药包长度为3.2 m的爆破孔平均破坏半径为0.57 m,较其他两排炮孔大20%以上。炮孔中药包长度是影响瓦斯抽放量的重要因素。爆破孔的平均单孔抽放量较控制孔高55%,爆破钻场较非爆破钻场平均单孔流量大49%。  相似文献   

填埋场排水层淤堵条件下渗滤液最高水位研究     

顾高莉  柯瀚  李育超  万晓丽  陈云敏 《岩土力学》2012,33(4):1094-1102

在Rowe和Fleming提出的用以计算淤堵时间简化模型的基础上,针对填埋场排水层淤堵时空分布特征,合理地作了进一步假设和推导,得到了可以反映淤堵发展的简化模型,推导出了排水层渗透系数的变化规律。采用水量平衡的单元分析方法,建立了淤堵条件下最高水位计算模型,获得了排水层最高水位深度的计算方法,并与稳态、瞬态方法进行比较。结果表明,无淤堵时得到的结果与瞬态结果一致,且都趋于稳态结果;淤堵较严重时水位受到显著影响,必须考虑淤堵。通过参数分析发现,前期渗透系数越小（后期越大）、排水距离越长、入渗速度越快、离子浓度越高,则淤堵对水位的影响越严重,同时提出考虑淤堵条件下改进排水系统的设计建议。  相似文献   

隧道掘进综合信息智能监控系统研究     

高文学  侯炳晖  孙西蒙  邓洪亮  周世生  陈宁宁 《岩土力学》2012,33(Z2):408-412

结合现代遥测技术,把选测断面传感器（频率类、电压电流类、开关量类、数字类等）数据采集、三维激光扫描、地质超前预报、爆破振动监测以及可视化监控融合在一起,实现隧道施工掌子面可视化实时显示与分析、隧道施工监测自动化数据采集与分析,形成隧道施工多元信息监测系统TIS(tunnel intelligentized monitoring system),确保复杂围岩地质条件下隧道施工安全。该系统测试项目的全面性、实时性和预警性对隧道施工的动态设计、施工管理以及提高施工过程的安全度等具有重要的现实意义。  相似文献   

Determination of In Situ Sediment Shear Strength from Advanced Piston Corer Pullout Forces     

Timothy J. G. Francis  Yir-Der E. Lee 《Marine Georesources & Geotechnology》2013,31(4):295-314

Abstract

The advanced piston cover (APC) has been used by the Ocean Drilling Program since 1985 for recovering soft sediments from the ocean floor. The pullout force measured on extracting the core barrel from the sediment is shown to correlate with the average shear strength of the sediment core measured in the ship's laboratory. A simple rule of thumb is derived relating the shear strength of the sediment to the pullout force. Multiple APC holes at individual sites allow the consistency of the pullout measurements to be assessed. The effects of different operational procedures during APC coring are also explored. Although generally applicable, the correlation between pullout force and laboratory measurements of shear strength breaks down for some APC holes, possibly because of the disturbance of some sediment types during the APC coring process. A better understanding of the physical process of APC coring, and its effect on the properties of the sediment both inside and immediately outside the core barrel, would indicate what confidence can be put on the measurement of pullout force as a way of evaluating the in situ shear strength of deep sea sediments.  相似文献   

Estimate of biological production in some stream invertebrates     

C. L. Hopkins 《新西兰海洋与淡水研究杂志》2013,47(4):629-640

Annual production of invertebrates was investigated in two streams, the Hinau and Horokiwi, in the North Island of New Zealand. Estimates were based on the instantaneous growth rate method, with adjustments made according to the number of generations produced per year. Production of primary consumers (herbivores and detritus feeders) was 7.6–72.1 g.m^‐2.y^‐1, and of secondary consumers (predators) 0.8–11.9 g.m^‐3.y^‐1. In both streams the lowest production was found in tree‐shaded situations. Production: biomass ratios ranged from 5.3 to 7.9 for primary consumers, and from 3.7 to 6.5 for secondary consumers. These ratios fall within the range of results found by workers in other countries. Fish in the two streams studied feed mainly on the primary consumers and so may be competing for food with invertebrate secondary consumers.  相似文献   

大庆徐家围子不同储层改造的干热岩潜力评估     

郭亮亮  张延军  许天福  金显鹏 《吉林大学学报(地球科学版)》2016,46(2):525-535

针对如何评估大庆徐家围子不同储层干热岩开采潜力的问题,基于徐家围子深井的地质和测井资料,对其深部存在的三种储层情况进行了划分。首先提出了各储层改造方案并建立了三维压裂模型;然后基于储层改造结果,采用水热耦合软件TOUGH2对其进行了换热分析;最终得出了不同储层的干热岩开采潜力。研究结果显示,徐家围子营城组储层是该区目前最适合进行干热岩开采的储层:根据天然裂隙发育程度,可以分为致密储层和天然裂隙发育储层,天然裂隙储层经清水剪切压裂后,采用三垂直井开采模式,最大注入速率30 kg/s,20 a产热量达17000~18500 kJ/s;根据地应力遮挡情况,可以分为遮挡层和无遮挡层,遮挡层和无遮挡层采用传统支撑剂型压裂后,采用三水平井(水平段2000 m)的开采模式,最大注入速率分别为20和32 kg/s,20 a的产热量分别为3500~5350 kJ/s和5600~7760 kJ/s。此外,虽然致密层产出热量远低于天然裂隙发育储层,但传统支撑剂型压裂和水平井技术结合后,致密储层也具有了开采干热岩的潜力。  相似文献   

干热岩资源和增强型地热工程:国际经验和我国展望   总被引：1，自引：0，他引：1  

许天福  袁益龙  姜振蛟  侯兆云  冯波 《吉林大学学报(地球科学版)》2016,46(4):1139-1152

干热岩（HDR）是一种没有水或含有少量水的高温岩体,保守估计地壳中3~10 km深处干热岩所蕴含的能量相当于全球所有石油、天然气和煤炭所蕴藏能量的30倍。增强型地热系统（EGS）是指通过水力压裂等工程手段在地下深部低渗透性干热岩体中形成人工地热储层,采出相当数量热能的人工地热系统。EGS的研究与开发已有40年的历史,但早期只局限在美国、英国、法国、日本、澳大利亚等国家,我国这方面的研究于近几年起步。目前干热岩的开发面临诸多挑战,如大体积人工裂隙热储的建造、实现EGS商业化需要进一步研究和技术开发等。本文回顾分析了国际上重要EGS示范场地建设和研究过程中所取得的经验和积累的教训,讨论了我国近几年的研究进展,希望为我国今后EGS研究和工程化示范提供参考和借鉴。  相似文献   

两种塑料排水板滤膜淤堵特性试验研究   总被引：1，自引：0，他引：1  

乐超  徐超  吴雪峰  金亚伟 《岩土力学》2014,35(9):2529-2534

在水力梯度逐级递增的条件下,采用饱和软黏土进行了两种不同塑料排水板（PVD）滤膜（外包土工织物）梯度比试验,探讨两种PVD滤膜的淤堵特性,并结合真空预压软基加固的实际工况进行分析。试验结果显示,随着水力梯度的递增,一种表观孔径大的新工艺PVD滤膜的梯度比呈现先上升后下降的总趋势,并最终趋于稳定,常规PVD滤膜的梯度比总体呈上升趋势,无法趋于稳定。研究表明,不同水力梯度对滤膜淤堵有着较大影响,新工艺PVD滤膜在真空预压实际工况（水力梯度较高）下的防淤堵效果优于常规PVD滤膜。PVD滤膜的淤堵问题与滤膜制作工艺、孔径和软黏土性质有关,其淤堵机制仍需进一步的研究。  相似文献   

Optimal root profiles in water-limited ecosystems     

《Advances in water resources》2014

The vertical distribution of roots in the soil is of central importance to the mass and energy exchange between the land and the atmosphere. It has been demonstrated that the vertical root profiles which maximize transpiration in numerical experiments reflect well the characteristics of root profiles observed in nature for water-limited ecosystems. Previous research has demonstrated how the optimal vertical root profile depends on both the mean annual precipitation (MAP) and the soil texture. Recently, in the climate literature, it has been suggested Chou et al. (2012) [5] that increased greenhouse forcing in the tropics can lead to a simultaneous decrease in the frequency and increase in the intensity of precipitation. In this paper we demonstrate how such a change in the statistical structure of rainfall, even with no change to MAP, requires deeper root distributions to maintain optimal water use. These results raise interesting questions for future studies of nutrient dynamics, the cost of additional below ground carbon allocation, and inter plant functional type competition.  相似文献   

Comparison of Ensemble Kalman Filter groundwater-data assimilation methods based on stochastic moment equations and Monte Carlo simulation     

《Advances in water resources》2014

Traditional Ensemble Kalman Filter (EnKF) data assimilation requires computationally intensive Monte Carlo (MC) sampling, which suffers from filter inbreeding unless the number of simulations is large. Recently we proposed an alternative EnKF groundwater-data assimilation method that obviates the need for sampling and is free of inbreeding issues. In our new approach, theoretical ensemble moments are approximated directly by solving a system of corresponding stochastic groundwater flow equations. Like MC-based EnKF, our moment equations (ME) approach allows Bayesian updating of system states and parameters in real-time as new data become available. Here we compare the performances and accuracies of the two approaches on two-dimensional transient groundwater flow toward a well pumping water in a synthetic, randomly heterogeneous confined aquifer subject to prescribed head and flux boundary conditions.  相似文献