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Acta Geotechnica - The main objective of this study was to propose an approach to estimate the peak friction angles of over-consolidated granular soil deposits by using the P-wave velocity and the... 相似文献
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试论残留型盆地研究思路和油气勘探方法 总被引：6，自引：0，他引：6
残留型地具有抬升剥蚀剧烈,原形盆地难以恢复,经历多期构造运动的改造和建造油气成藏动力学过程复杂,热演化程度较高,油气保存条件复杂等特点,但是残留型盆地油气资源丰富,勘探前景广阔,依据残留型盆地的特征和油气资源潜力,提出应全面,发展地认识盆地,静动结合地研究盆地,运用先进而实用的新技术新方法评价盆地,按照勘探程序勘探盆地,在研究工作上应以分地及其邻区作为整体研究对象,以区域地质研究一石油地质研究－综 相似文献
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Dynamic Analysis of Subway Structures Under Blast Loading 总被引：3，自引：1，他引：2
Huabei Liu 《Geotechnical and Geological Engineering》2009,27(6):699-711
Public transit systems have become one of the targets of terrorist attacks using explosives, examples of which are the 1995
attack on Paris subway and the 2004 attack on Moscow subway. Considering the intense threats of terrorist attacks on subway
systems in metropolitan areas, explicit three-dimensional Finite Element method was used to investigate the dynamic response
and damage of subway structures under internal blast loading. The study was motivated by the fact that explosion in subway
structure may not only cause direct life loss, but also damage the subway structure and lead to further loss of lives and
properties. The study based on the New York subway system, and investigated the influences of various factors on the possible
damage of subway tunnel, including weight of explosive, ground media, burial depth and characteristics of blast pressure.
A mitigation measure using grouting to improve ground stiffness and strength was also analyzed. Considering the amount of
explosive terrorists may use, the present study focused on small-diameter single-track tunnels, which are more vulnerable
to internal blast loading and are common in New York City. Blast pressure from explosion was applied to lining surface assuming
triangle pressure–time diagram, and the elasto-plasticity of ground and lining as well as their nonlinear interaction was
taken into account in the numerical model. It is found from the numerical study that maximum lining stress occurred right
after explosion, before the blast air pressure reduced to the atmospheric one, and it was more dependent on the maximum magnitude
of air pressure than on the specific impulse, which is the area below the pressure–time curve. Small tunnels embedded in soft
soil, with small burial depth, might be permanently damaged even by modest internal explosion that may be perpetuated by terrorists. 相似文献
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A constitutive model for dense gravelly soils was developed to reproduce their responses under cyclic loadings. Its application aims at nonlinear dynamic analyses of earth structures involving gravelly soils, such as rockfill dams and railroad ballasts. The framework of generalized plasticity was modified to incorporate the concept of stress distance for better simulation of unloading and reloading responses. It was then combined with the theory of critical state soil mechanics to develop the constitutive model. The model has the following important features: unified simulation of particle breakage through translating critical state line, smooth transition from unloading to reloading in the stress space, and proper modeling of cyclic hysteresis, cyclic densification, and cyclic hardening of dense gravelly soils. Most of the model parameters can be obtained through simple calculation using conventional triaxial test results, and their calibration process was discussed. The model was used to simulate the cyclic responses of three gravelly soils with satisfactory accuracy. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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二连盆地洪浩尔舒特凹陷下白垩统构造特征与沉积体系研究 总被引：2，自引：0，他引：2
在深入研究洪浩尔舒特凹陷大量岩芯、测井和地震资料的基础上，证实这一半地堑相似于北美东部裂谷，而不同于东非裂谷。同时发现边界断层各段位移量最小处为古河流入口地点，后者堆积横向的粗粒三角洲，使断陷被分割成若干次凹，导致构造和沉积的复杂化。断陷中，体系域发育受枢纽断层控制，LST主要分布于下降盘。在等时格架内，进行地震地层学-沉积相分析是掌握储层分布，揭示深部、隐蔽油藏的有力手段。最后判定该凹陷远景在于勘探LST的多种沉积体系。 相似文献
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在常规应力水平下颗粒发生破碎是钙质砂有别于其他砂土的重要性质之一,且由于颗粒破碎的存在,使用传统的本构模型无法很好地模拟钙质砂的力学行为。因此本文以最为普及的本构模型之一--邓肯-张E-B模型为基础,对其进行颗粒破碎方面的修正以得到一个能用于钙质砂的本构模型。具体方法为:首先本文采用Hardin提出的相对破碎Br这一指标来度量颗粒破碎的大小。之后研究分析得出了颗粒破碎对邓肯-张模型参数(内摩擦角φ、割线模量E50及体积模量B)的影响规律。然后通过颗粒破碎与输入能量之间的关系将各状态下无法直接确定的相对破碎Br与可确定的应力-应变状态联系起来。最终得到了一个考虑颗粒破碎的钙质砂修正邓肯-张E-B模型。为验证模型的准确性及适用性,本文还使用该模型对4种不同粒径范围且试验围压不同的钙质砂的三轴排水行为进行了模拟。结果表明拟合效果较好,模型能适用于各种不同粒径范围的钙质砂,并且在颗粒破碎较大的情况下明显优于传统邓肯-张模型。 相似文献
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Response of circular tunnel with imperfect interface bonding in layered ground subjected to obliquely incident plane P or SV wave 
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下载免费PDF全文 A semianalytical procedure is proposed for evaluating the internal forces of circular tunnel with imperfect interface bonding in layered ground subjected to an obliquely incident plane P or SV wave. In this study, the hoop bending moment and hoop axial force are related to the free‐field responses of the ground. A one‐dimensional numerical approach is firstly presented to obtain the free‐field responses of a layered half‐space with an obliquely incident plane P or SV wave propagation. Then, the free‐field stress state is transformed and decomposed in the polar coordinate system. The internal forces of tunnel caused by the isotropic stress state and the pure shear state are calculated and then summed up to obtain the overall analytical solutions. Finally, the validity of the proposed semianalytical procedure is demonstrated by numerical examples. 相似文献
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Deformation analysis of reinforced soil retaining walls—simplistic versus sophisticated finite element analyses 总被引：2，自引：2，他引：0
Over the last two decades, different kinds of modular block have been increasingly used in the geogrid-reinforced soil retaining
walls. The simulation of such wall behavior, which involves interactions between different structural components and backfill
soils, requires a rigorous numerical procedure. Finite element is usually a preferred method, but this procedure, especially
the soil constitutive models, is of different degrees of sophistication. It is always an issue of how simple or sophisticated
should an analysis be conducted in replicating the actual behavior. In this article, a full-scale test wall was used to validate
simplistic and sophisticated finite element analyses. Different types of finite element and material models were used in the
two kinds of analysis to differentiate the level of simplicity or sophistication. The results obtained from stress-deformation
analyses are presented and compared. It is shown that for wall construction that involves static loading conditions, simplistic
nonlinear elastic and sophisticated elastoplastic analyses produced close and acceptable results. 相似文献
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在集宁盆地商都坳陷，首次应用丰富的孢粉、介形类和轮藻等化石资料论证并命名了一套新地层，自下而上为高勿素组和大囫囵组，在高勿素组中分别建立了孢粉Ⅰ．Cyathidites—Aequitriradites—Pilosisporites—Tricol popollenites组合；介形类Ⅰ．Mongolocypris infidelis—M．tera—M．longa组合；轮藻I．Obtusochara niaoheensis—Atopochara alanensis—S phaerochara datongensis组合。在大囫囵组中建立了孢粉Ⅱ．Schizaeoisporites—Taxodiaceaepollenites组合，包括2个亚组合，即①Cicatricosisporites-Classopollis亚组合，②Tricolpites-Polyporites亚组合；介形类Ⅱ．Mongolocypris cf．infidelis-M．cf．tera组合；轮藻Ⅱ．Grambastichara yuntaishanensis—Hornichara productas—Raskyaechara wumengensis组合。根据上述微体古生物化石，认为高勿素组相当于早白垩世晚期的阿尔布期，大囫囵组相当于晚白垩世早期的赛诺曼—土伦期。 相似文献