共查询到20条相似文献，搜索用时 31 毫秒
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通过对某一级公路路基填土的天然含水量、液限、塑限、颗粒组成、矿物成分、自由膨胀率、胀缩总率等试验研究,运用塑性图,并综合各项指标对路基填土的膨胀性做了评价。结果认为,此路基填土为高液限和塑限的淤泥质软土,天然状态下具有弱膨胀性。通过对路基填土的击实试验和承载比试验表明,填土压实之后具有一定的膨胀性,在含水量变化差异性影响下的胀缩变形可能导致路基开裂。 相似文献
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风积沙路基的处理一直是沙漠公路建设面临的难题, 土工格室加固方法可为沙漠公路建设提供一条新路径, 结合S21线(乌鲁木齐-阿勒泰)沙漠公路路基现场试验, 研究不同路基深度动力响应特征, 对土工格室加固风积沙性能探究具有重要的价值及意义。结果表明: ①测试车速对路基不同深度处动应力、动加速度和动速度的时程曲线波动性影响较大, 且提高车速时, 动速度峰值、动加速度峰值和动应力峰值都出现了明显的增加; ②随着路基层深度的不断增加, 动速度幅值、动加速度幅值和动应力幅值均呈现出逐渐衰减的趋势, 其中在土工格室加固风积沙层衰减幅度最大; ③沿路基横断面水平方向上, 动速度幅值、动加速度幅值和动应力幅值均呈指数型衰减的趋势, 距振动源水平距离为5 m时, 其幅值衰减至10%左右, 可将此水平范围作为工程设计参考值。 相似文献
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瑞雷面波在灌浆加固路基检测中 ,既可利用面波波速等值线断面发现可能存在的软弱部位 ,在三维空间上宏观评价灌浆加固效果 ,还可结合少量动力触探 ,间接计算路基承载力。文章从工程实例出发 ,着重探讨了实际工程应用中路基加固效果的宏观评价及触探击数与波速回归分析中的抽样问题 相似文献
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Strong fluctuation of seabed, abrupt variation in depth and dip of seabed bring seismic imaging problems, such as irregular reflection waves, obvious multiple waves, serious lateral wave development, poor imaging on base surface and depression structure, low signal-to-noise ratio of middle and deep layers. In this paper, Gaussian beam migration imaging method is used to analyze the imaging effect of rugged seabed in deep water area, and the ray tracing method of wavefront construction method is used to analyze the kinematic characteristics of seismic waves. By improving the design of seismic data acquisition and observation system, imaging quality of fine structures is improved. 相似文献
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利用重、磁、电综合物探勘测研究了郑州南浅层地热田。该地热田有明显的重磁电异常；重力场沿断裂呈现出条带状或串珠状的异常特征；浅层热源区有着明显的强负磁异常，深层热源区在区域地磁场上有弱负磁异常显示；热源区上部有低电阻率异常显示。本文还对郑州市深浅热源区的边界及其异常特征做了初步推断和解释。 相似文献
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《世界地质(英文版)》2016,(2):95-101
With the increasing complexity of prospecting objectives,reverse time migration (RTM)has attracted more and more attention due to its outstanding imaging quality.RTMis based on two-way wave equation,so it can avoid the limits of angle in traditional one-way wave equation migration,image reverse branch,prism waves and multi-reflected wave precisely and obtain accurate dynamic information.However,the huge demands for storage and computation as well as low frequency noises restrict its wide application.The normalized cross-correlation ima-ging conditions based on wave field decomposition are derived from traditional cross-correlation imaging condition, and it can eliminate the low-frequency noises effectively and improve the imaging resolution.The practical proce-dure includes separating source and receiver wave field into one-way components respectively,and conducting cross-correlation imaging condition to the post-separated wave field.In this way,the resolution and precision of the imaging result will be promoted greatly. 相似文献
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PS测井技术是地震勘探方法之一,也是一种简便、快速、准确的原位测试技术。该文介绍了单孔法PS测井的原理及其在铁路工程勘察中的应用,主要包括根据等效剪切波,进行建筑抗震场地类别划分,铁路工程抗震场地类别划分。根据岩土动力学参数,达到评价岩体质量和划分围岩类别目的,利用剪切波速法估算岩土的承载力基本值。通过青岛机场隧道场地的工程实例说明了PS测井技术在岩土工程勘察设计中的应用情况及应用效果。 相似文献
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鲁西南(中西部)地区普遍存在地下水中氟化物及矿化度含量较高的问题。电阻率与地下水矿化度关系密切,高氟又易与高矿化度伴生存在,因此赋存高矿化度地下水的黏土层与赋存可饮用地下水砂土层电性上的差异为利用电法在该地区勘查出可饮用地下水提供了基础条件。综合区内区域地质、水文地质及地球物理特征,对重点区的电测深曲线进行了精细的定性及定量解释,划分出重点区内含水层的埋深、黏土层及砂土层分界线,推断出了深层高阻层主要为含淡水砂土层。根据物探推断成果在牡丹区沙土集及曹县常乐集重点区分别施工了2眼钻井。结果表明,钻井出水量丰富,水质较周边有明显改善,直流电测深是在该区域寻找可饮用水资源的一种经济、有效的勘查手段。 相似文献
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The Duobaoshan mine area in Heilongjiang is located in the northeast section of Xingmeng orogenic belt and is in the west side of Hegang Mountain-Heihe fault zone .There exist many deposits in this area , and its metallogenic conditions are superior , which has been one of the hotspots in geological prospecting and metal -logenic research in Northeast China .On the basis of previous studies , the authors used the EH-4 electromagnet-ic imaging system to carry out the data acquisition of three survey lines in Woduhe Village , Duobaoshan Town , Nenjiang County .Through the analysis of apparent resistivity section under TE and TM polarization modes , in-tegrating regional geological data , it is concluded that:①the electrical characteristics of the metal ore in this area show a relatively low resistance , and according to its resistivity difference with surrounding rocks , the geo-metrical structures and apparent resistivity parameters of the low resistivity bodies in the lower section of the sur -vey line are defined , and the electrical anomalies can be identified;②faults F1 and F2 may have a good metal-logenic environment , so they are recommended for further exploration;③low resistance metal ore bodies have good correlation with local small structures or faults , which may play an iconic role for the delineation of key target areas;④in the process of using apparent resistivity to define the geometric structures of ore bodies un -derground , comprehensive analysis integrating the advantages of TE and TM models should be carry out to achieve more reliable inversion results . 相似文献
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采用有限元方法模拟隧道地震波场,采用波场快照与时间记录相结合的方法,研究空洞对隧道地震波场传播的影响,并对含空洞模型的时间记录进行处理,得到数值模型的速度云图和反射层位图。经数据处理表明,采用TSPwin设定默认值处理得到的速度云图与模型设定的空洞位置比较一致,在提取反射层位图上,空洞反射层呈现条带状特征,需要结合速度云图来确定空洞位置,且P波预报的准确性相对较高。对TSP系统的抗噪性进行研究,表明其具有良好的抗噪性能。最后通过对工程实例的处理,验证了数值模拟所得的结论。 相似文献
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Filling velocity and thickness of soft layer are major factors affecting subgrade stability according to an example study by means of finite element stress method (FESM). A case is studied and shows that the subgrade was slided because of excessive filling velocity. To determine a reasonable filling velocity is a key problem to a subgrade with marine soft soil. 相似文献
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结合青藏高原东南缘软弱带的分布及地震活动性的深度空间特征，提出强震孕育的壳幔耦合模型。利用中国国家数字地震台网和四川云南区域数字地震台网及布设在青藏高原东南缘的地震台站所记录的远震SKS波形资料，通过剪切波分裂得出上地幔各向异性结果数据，描绘出青藏高原东南缘的上地幔各向异性图像；再分别同该地区GPS观测的速度场数据、区域构造应力场数据和13 km深度的介质密度数据进行相关性处理与分析，并针对本文提出的孕震模型进行一定程度的验证。对形变场和应力场耦合特征的研究表明，各向异性的快慢波时间延迟、快波偏振方向总体分别与GPS 测量的地壳运动速度场方向变化和水平最大应力方向相关性较大，壳幔各圈层相互作用及软流圈的流动所展示的地震各向异性都与应力传递机制息息相关。通过相关分析可以得到壳内软弱带（低速高导体）在壳幔耦合运动研究中的关键作用，而该类耦合运动与地震孕育息息相关。 相似文献
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As an important geophysical tool,high density electrical technique infers the underground geological structures by processing and inverting the apparent resistivity data.Currently,the false anomalies have been frequently occurred in the graph of apparent resistivity pseudo-section or inverted geoelectrical section obtained from high-density electrical technique,and are difficult to remove.In this study,the authors explain the mechanism of the false anomalies and put forward the horizontal differential field method to identify the false anomalies.Based on the analysis of modeling results,this method is applied in the surveying data in Xinlei Quarry of Jiuquan,and the results confirm the effectiveness of the horizontal differential field method. 相似文献
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视电阻率定义在电法勘探中得到广泛的应用。目前在频率域电磁法中常常采用远区视电阻率定义。由于在频率域中收发距并非足够大,以致在低频段远区定义视电阻率往往不能反映地下电阻率值。我们定义全区电阻率及引入校正系数K,经二层三层模型及野外实测资料的计算,证明了方法的有效性。 相似文献
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《山地科学学报》2021,(10)
The settlement of widened highway subgrade in mountainous area is not only affected by the interaction between new and existing subgrade, but also seriously restricted by the external retaining wall. Based on the practical engineering of half-filled and half-cut widened mountainous highway subgrade with external balance weight retaining wall(BWRW), a sophisticated finite element numerical model is established. The evolution law of subgrade settlement is revealed during the whole process of new subgrade filling and BWRW inclination after construction. The settlement component of subgrade is clarified considering whether the existing pavement continues to be used. The results show that the additional settlement caused by the BWRW inclination after construction cannot be ignored in the widening and reconstruction of mountainous highway subgrade. In addition, pursuant to the comprehensive design of subgrade and pavement, the component of subgrade settlement should be determined according to whether the existing pavement continues to be used, while considering the influence of BWRW inclination after construction. When the existing pavement continues to be used, the settlement of the existing subgrade is caused by the new subgrade filling and the BWRW inclination after construction. On the contrary, the settlement is only caused by the BWRW inclination after construction. 相似文献
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选取2008~2018年茅山断裂带及周边82个测震台站记录到的516个近震Pg、Sg到时数据,采用双差地震层析成像方法对茅山断裂带及邻区进行地震重定位和三维P波速度结构的联合反演,并分析溧阳历史上两次破坏性地震与速度结构的关系。结果表明,地震重定位后残差显著降低,研究区大部分地区横向分辨率可达0.2°。P波的速度结构横向差异变化比较明显,反演后的速度与初始速度模型之间的变化率基本在±10%左右。茅山断裂带两端呈现高速特征,中段表现为低速结构。溧阳震源区1974年MS5.5地震发生在深变质岩系内的低速层上,而1979年MS6.0地震发生在深变质岩系与浅变质岩系边界上,这两次地震的发震原因可能与具有塑性流变特性的低速体和速度梯度较大的转换复合位置容易产生应力集中有关。 相似文献
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为分析2022-01-02云南宁蒗MS5.5地震前后波速比的时空演化特征,采用单台多震和达法,计算2020-01-01~2022-01-10云南数字地震台网记录的满足计算条件的地震震相到时数据,分析云南地区59个台站波速比以及距离震中最近的LGH和NLA台记录的震后序列波速比变化情况。结果表明：1)宁蒗MS5.5地震发生在滇西北波速比高值区域,且该区域随时间推进呈扩大趋势,可能是在孕震过程中震中附近裂隙有流体渗入达到水饱和状态,从而导致波速比增大;2)震中100 km范围内4个台站波速比大致呈现持续下降-发震的演化过程,距离震中最近的LGH台波速比下降时间稍晚于其他3个台站,初步分析认为,波速比变化出现时间与震中距呈负相关;3)震后地震序列波速比变化与余震活动情况具有较好的对应关系,最大余震发生前波速比出现突降变化;当地震序列呈现正常衰减趋势,波速比维持稳定低值。 相似文献