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131.
132.
不同压实度荆门弱膨胀土的一维膨胀-压缩特性 总被引:1,自引:0,他引:1
为探讨压实膨胀土的体变行为,以荆门弱膨胀土为研究对象,借助高压固结仪对6种制样压实度下的膨胀土试样进行了一维无荷载膨胀和含一次卸载-再加载循环的压缩试验。基于膨胀试验结果,构建了膨胀时程方程,通过参数分析,明确了方程参数的物理意义,并建议了膨胀时程曲线3阶段的划分方法。基于压缩试验结果,探讨了固结屈服应力、压缩指数Cc、回弹指数Cs、膨胀力与制样压实度、土体结构性、膨胀势、孔隙比的相关关系。试验结果及其分析表明,膨胀土体积变化是膨胀势与外部荷载、湿度变化的耦合作用结果,且具有强烈的水-力路径依赖性。 相似文献
133.
柴达木盆地西部新生界异常高压:分布、成因及对油气运移的控制作用 总被引:10,自引:6,他引:10
如同世界上其它新生代沉积盆地那样,柴达木盆地在一定深度,区域上普遍存在异常高压。异常高压出现在快速沉积的厚层泥质岩中,水热增压效应明显,而且在上新世末至今发生了强烈的以水平挤压为主的构造运动,因此异常高压的形成是由于不均衡压实作用和构造挤压作用所引起的压应力增大以及热液压力引起流体体积的变化。异常高压是油气运聚的一种重要动力来源:在油气运移中,可以使上覆封隔层产生大量微裂缝,油气向上运移到在较低压储集层中,也可以使封闭性断层开启,通过断层进行侧向运移。 相似文献
134.
135.
使用非标准击实仪进行单层击样,获取非标准击实状态下单层击实样的密度与击实功及含水率之间的关系,并进一步以得到的击实样获得其抗剪强度。发现当击实功小到一定程度时,击实密度随含水率的增大而不断增大,两者近似线性变化,无峰值出现。密度峰值对应的含水率与抗剪强度峰值对应的含水率有一个差值,其值在3.4%~5.7%之间。内摩擦角随含水率增大而减小的规律仅适合于一定的击实功。内摩擦角在较小的击实功下有峰值出现,但随着击实功的增大,内摩擦角的变化呈线性而非曲线形式。另外,针对土工室内模型试验的重塑土样制备问题,结合试验数据,给出了试验最优制样参数,并初步提供了评价指标?。 相似文献
136.
辽宁岫岩金矿是岩浆热液成因的石英脉型金矿床,然而矿区内的一系列石英脉体尽管其空间分布上关系密切,但其矿化程度却有显著差异。本文就这种差异的原因从区域构造应力场-岩体形态-岩石力学性质-控矿(脉)断裂的性质及时、空定位的相关上进行了深入分析探讨,认为岩体形态、岩石物理力学性质是影响断裂时、空定位和性质的主要因素,而且是控制矿化程度差异的根本因素。井由此推断,在1 ̄#,2 ̄#断裂带南东侧延伸的深部有望找到矿体。 相似文献
137.
干密度是评价软土固化质量的重要指标,一般通过室内击实试验获得。以氯氧镁水泥(MOC)为结合料,砾石土为固化对象,研究了原料配比对MOC固化砾石土击实性能的影响。通过室内击实试验,考察了轻烧镁粉掺量、卤水浓度、卤水掺量和活性MgO/MgCl_2物质的量比(Mg/Cl比)影响混合料干密度的规律。结果表明:MOC固化砾石土击实料的干密度随卤水掺量增加先增加后降低,随轻烧镁粉掺量及Mg/Cl比的增加而先增加后降低,随卤水浓度及轻烧镁粉掺量的增加而增加,随卤水浓度增加及Mg/Cl比降低而增加。 相似文献
138.
Compaction of granular soils by uniform vibration equivalent to vibrodriving of piles 总被引:2,自引:0,他引:2
Summary A programme of laboratory tests was undertaken to identify the volume reduction of a range of granular soils in response to uniform vibration. The purpose of the tests was to quantify the potential compaction settlement of granular soils due to vibrations typical of those experienced when sheet or bearing piles are installed or extracted by vibrodriver. The vibrations in soils within 2–20 m of a vibrodriven pile are well defined as sinusoidal, at the frequency of the vibrodriver, and typically in the range of 1.0g down to 0.02g (whereg=gravitational acceleration). Thein-situ conditions were replicated in the laboratory by vibration of a Rowe cell containing a soil sample. This allowed control of stresses before and during vibration. Tests were conducted on nine granular soils, ranging from uniform Leighton Buzzard sands to a sandy fine-to-medium gravel. Soil samples were prepared at minimum relative density, generally in the saturated state, but also dry and partly saturated. Each sample was consolidated at a selected effective stress of between 10 and 100 kPa. It was then vibrated vertically at increments of controlled acceleration, under conditions of free drainage and maintained confining stress. Reduction in sample thickness was measured continuously. Results showed that even in a small, drained, sample the full volume reduction was reached only after many minutes, although the early response was more rapid. The trends of results showed that: increased surcharge pressure reduced the subsequent vibratory compaction; well-graded soils showed greater compaction than more uniform sands; compaction increased markedly when acceleration exceeded 1 g; saturated soils showed larger compaction than dry and partially saturated soils; compaction was influenced little by frequency, although rate of compaction reduced with frequency increase. 相似文献
139.
根据自己研制的高压控温泥岩压实仪,对我国三水、泌阳和黄骅三个中新生代含油(气)盆地和拗(凹)陷进行了压实模拟,从而证实了我国东部三个中新生代盆地和拗(凹)陷存在四个压实阶段,证实了泥质沉积物和地温梯度是严重影响压实和流体运移的主要因素,同时还证实了三水盆地和泌阳凹陷存在着严重的剥蚀。 相似文献
140.
The >200 km long Moonlight Fault Zone (MFZ) in southern New Zealand was an Oligocene basin-bounding normal fault zone that reactivated in the Miocene as a high-angle reverse fault (present dip angle 65°–75°). Regional exhumation in the last c. 5 Ma has resulted in deep exposures of the MFZ that present an opportunity to study the structure and deformation processes that were active in a basin-scale reverse fault at basement depths. Syn-rift sediments are preserved only as thin fault-bound slivers. The hanging wall and footwall of the MFZ are mainly greenschist facies quartzofeldspathic schists that have a steeply-dipping (55°–75°) foliation subparallel to the main fault trace. In more fissile lithologies (e.g. greyschists), hanging-wall deformation occurred by the development of foliation-parallel breccia layers up to a few centimetres thick. Greyschists in the footwall deformed mainly by folding and formation of tabular, foliation-parallel breccias up to 1 m wide. Where the hanging-wall contains more competent lithologies (e.g. greenschist facies metabasite) it is laced with networks of pseudotachylyte that formed parallel to the host rock foliation in a damage zone extending up to 500 m from the main fault trace. The fault core contains an up to 20 m thick sequence of breccias, cataclasites and foliated cataclasites preserving evidence for the progressive development of interconnected networks of (partly authigenic) chlorite and muscovite. Deformation in the fault core occurred by cataclasis of quartz and albite, frictional sliding of chlorite and muscovite grains, and dissolution-precipitation. Combined with published friction and permeability data, our observations suggest that: 1) host rock lithology and anisotropy were the primary controls on the structure of the MFZ at basement depths and 2) high-angle reverse slip was facilitated by the low frictional strength of fault core materials. Restriction of pseudotachylyte networks to the hanging-wall of the MFZ further suggests that the wide, phyllosilicate-rich fault core acted as an efficient hydrological barrier, resulting in a relatively hydrous footwall and fault core but a relatively dry hanging-wall. 相似文献