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1.
地铁隧道爆破开挖对地表建筑物的影响   总被引:1,自引:0,他引:1  
通过对深圳地铁隧道爆破开挖时爆破震动监测数据的分析和研究,总结出爆破震动对地表建筑物产生危害的主要影响因素,并根据现场测定数据,拟合出地震速度、药量大小与爆源距离之间关系式。现场测定与研究表明:必须重视地铁隧道爆破地震规律及其对各种建筑物和构筑物影响的研究,才能充分发挥爆破技术的经济效益和最大限度地降低爆破振动的危害。  相似文献   

2.
以位于长江中游支流沅江干流的某水电站混凝土围堰拆除爆破为工程背景,需要爆破拆除的混凝土围堰与县城的直线距离不超过2 km,与最近的一条坝顶公路桥的最小距离为3 m,所以控制爆破振动势必对本工程有着重要的意义。通过对该工程现场爆破试验进行质点振动监测,测取离爆源不同位置下的质点振动速度的监测数据,同时采用回归分析法对数据进行分析,得出爆破地震波在钢筋混凝土大坝结构中的衰减规律,结果表明,使用分段微差爆破技术可有效控制拆除爆破对大坝的振动影响;依据《爆破安全规程》对钢筋混凝土结构质点安全振动速度的要求(v≤5 cm/s),证明试验爆破初步设计方案及爆破参数k,α较为合理,可为后期爆破方案确定和保证坝体安全稳定性提供依据,也可为类似工程提供工程经验。综合以上试验爆破参数和监测数据得出以下建议:最大单响药量控制在27 kg以下;需要采取一些外在减震措施;要注意地震波的主频率变化范围,防止共振现象的发生。  相似文献   

3.
郑小龙  李海港 《江西科学》2020,38(4):562-567,610
为研究某铁矿露天爆破振动对尾矿库稳定性的影响,在尾矿坝对其露天开采爆破作业进行爆破振动监测与试验,统计分析爆破振动的主频和质点振动峰值速度,基于萨道夫斯基公式对露天开采爆破最大允许药量与安全距离进行预测,最后对尾矿库进行爆破振动液化分析。结果表明:振速控制标准在0.1~0.5 cm/s范围内,同一振速控制标准时最小安全距离随着齐爆药量的增加而增大,振速控制标准越大,当齐爆药量增加时最小安全距离增幅越小;经过振动荷载作用后,坝体内部无液化区域,浸润线基本保持不变。通过掌握药量和距离控制爆破振动对尾矿坝稳定性的影响,为控制与优化爆破施工参数提供依据。  相似文献   

4.
路堑爆破开挖地震效应分析   总被引:4,自引:1,他引:4  
在分析爆破地震效应的主要控制因素地震速度与地震频率基础上,根据现场测定数据,拟合出地震速度、药量大小与爆源距离之间关系式。分析了振动频率对构筑物的影响和爆破地震与天然地震的区别,提出了爆破安全距离的确定并验证了爆破安全距离计算方法以及地震速度作为破坏判据可行性和正确性。试验测定结果与研究表明,必须重视爆破地震规律及其对各种建筑物和构筑物影响的研究,才能充分发挥爆破技术的经济效益和最大限度地降低爆破振动的危害。  相似文献   

5.
结合武汉市轨道交通2号线工程背景,采用现场监测和动力有限元数值模拟相结合的研究方法,对超浅埋通道下台阶爆破开挖地表振动传播规律进行研究。同时,为研究上台阶开挖空间对爆破地震波传播特征的影响,对通道全断面爆破开挖的地表振动传播规律进行数值模拟分析。研究结果表明:下台阶爆破开挖工况下,沿通道开挖导洞轴线方向,由于应力波的绕射,掌子面前方5 m处地表质点峰值振速达到最大值;垂直于通道开挖导洞轴线方向,掏槽孔孔底连心线中点正上方地表质点与爆源距离最小,但峰值振速并不是最大,且质点两侧2 m范围内,随着爆心距的增加,峰值振速不断增大。全断面爆破开挖工况下,沿通道开挖导洞轴线方向,掌子面前方2 m处地表质点峰值振速达到最大值;垂直于通道开挖导洞轴线方向,掏槽孔孔底连心线中点正上方地表质点峰值振速最大,且随着爆心距的增加,峰值振速不断减小。对比通道下台阶爆破开挖和全断面爆破开挖2种工况下地表质点振动特征,上台阶开挖空间的存在阻隔了应力波的传播,在一定空间范围内影响爆破地震波的传播特征,能够有效降低地表质点峰值振速。  相似文献   

6.
隧道爆破振动对古建筑影响的试验研究   总被引:1,自引:1,他引:0  
结合南京地铁四号线鼓楼站区间隧道爆破开挖工程,通过现场试验的方法,得到了适用于现场地质条件下的三个方向上的萨道夫斯基预测公式,为爆破开挖设计提供参考。结果表明:地表质点垂直方向振动速度峰值距离爆源近时,比两个水平方向振动速度峰值大,远处时则最小;且在30 m内迅速衰减。鼓楼城阙垂直方向的振动速度峰值最大,碑楼水平方向的振动速度峰值最大,振动速度峰值随着药量增加总体上呈现增加,采取微差爆破可有效减小振动速度峰值。  相似文献   

7.
以大连地铁2号线208标马湾区间浅埋暗挖隧道下穿魏台桥特殊地段为研究对象,通过三维有限元程序仿真模拟以及工程现场动态监测对比,研究爆破振动对既有构筑物的动力响应问题。研究结果表明:爆破地震波振动速度峰值在距爆源较近区域的衰减速度远大于爆源远区,同时沿深度方向的衰减速度大于水平方向;爆破地震波在构筑物中会出现两次或多次峰值振速,说明爆破冲击波具有强烈的多次反射性,对结构的破坏性也较大;不同深度处的监测点其振速达到峰值的时间和峰值大小均不同,越靠近爆源,受扰动的峰值越大,时间越短;近距离爆破会对既有隧道衬砌安全性产生很大影响,在既有隧道衬砌迎爆侧拱腰部位为薄弱区。  相似文献   

8.
采用CDSP(WS-INV)海量数据数字记录仪及Vib,SYS数值振动信号采集分析系统对海阳核电采石场岩石爆破及取水明渠水下炸礁进行爆破振动监测。通过测点距离爆源间的距离以及测得的测点上垂直、水平径向二个方向速度确定出K、α(与爆破点至计算点间的地形、地质条件有关的系数和衰减系数)和最大段起爆药量值。进而指导后续爆破作业。  相似文献   

9.
为研究矿山爆破地震波传播过程中的混沌特性,运用相空间重构理论对距爆源不同距离处爆破地震波进行相空间重构,计算延迟时间和关联维数.研究结果表明:随着传播距离的增加,爆破地震波时间序列的关联维数呈线性递减并趋于稳定饱和值;关联维数越大,混沌特征越明显,爆破地震波时间序列的混沌性是其本质特征.  相似文献   

10.
为降低小间距隧道爆破开挖中爆破振动对既有隧道产生的影响,确保其正常运营,设置减震孔是一种有效的控爆措施。利用ANSYS/LS DYNA软件对减震孔在不同布置位置和形式的掏槽爆破进行数值模拟计算,发现:在传播方向上,随着减震孔与爆源距离L的增大,质点水平方向峰值振动速度和质点峰值振动速度先减小后增大,而质点垂直方向峰值振动速度相反。当距离L为1 m时,布置双排梅花形减震孔效果最好,减振效率为10%~20%,其中垂直方向减振效率最高达到45%,并将小间距既有隧道中墙体迎爆侧破坏作为安全评价基准。通过理论计算得出减震孔在隧道爆破中的衰减规律,为爆破振动强度的预测提供依据。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

14.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

15.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

16.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

17.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

18.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

19.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

20.
The non-orthogonal localized molecular orbital(NOLMO)is the most localized representation of electronic degrees of freedom.As such,NOLMOs are thus potentially the most efficient for linear scaling calculations of electronic structures for large systems.However,direct ab initio calculations with NOLMO have not been fully implemented and widely used,partly because of the slow convergence issue in the optimization of NOLMO.We devel-  相似文献   

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