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71.
72.
ZHOU Gangyan ZOU Jiazhong 《国际泥沙研究》1997,(1)
I.m~UCrIONBedloadisthesedimentwhichmovesalongtheriverbedintheformofrolling,slidingandsaltation.BedloadmaycreatemanyproblemsintheoperationandmaintenanceofnavigationchannelandinthedevelOPmentofhydroelectricity.Dataofbedloaddischargearealsorequiredinthedesignofreservoir,inwhichtheinflowbedloadareallactuallytrapped.Thewaysofbedloadmotionaredifferentfordifferentsizes.Thus,itisextremelydifficulttodeterminethebedloaddischargeaccurately.Manyequationshavebeenproposedtocalculatethebedloaddischarge.H… 相似文献
73.
Yousheng Xu Hongsen Xie Jie Guo Haifei Zheng Yueming Zhang Maoshuang Song 《中国科学D辑(英文版)》1997,40(4):398-402
NaCI-H2O is the most fundamental ternary system in geology. Until now, the measurements of electrical conductivity of NaCl solutions
are still little at high pressures (> O.5 GPa) We measured the conductivity of 0.01 m NaCl solution at 0.4–5.0 GPa and 25-500°C.
The results are consistent with that of Quist and Marshall (1968) at 0.4 GPa. The conductivity of NaCl solution increases
with increasing temperature. The results also show that the conductivity of NaCl solution changes little with increasing pressure
below 1.5 GPa and changes rapidly with increasing pressure above 1.5 GPa. The rapid increase of the conductivity of NaCl solution
may play an important role in many geological processes (such as the genesis of ore deposits under hydrothermal condition)
and other fields.
Project supported by the National Natural Science Foundation of China. 相似文献
74.
通过分析、比较1996--2003年喀什地震台站记录到的新疆伽师及附近地区发生的多次6级地震的地磁前兆异常特征,发现在这几组地震活动过程中喀什地震台的地磁表现出不同的异常特征,说明与地震破裂特征有更深层次的相关性,且地磁响应比异常和总强度差值异常在一定程度上反映了台站周围小范围的震源区介质电性结构的变化。巴楚-伽师6.8级地震前地磁异常特征并不十分突出,有别于1996—1998年伽师强震群震前地磁异常量较丰富的特点。 相似文献
75.
The dynamics of finite-amplitude bed forms in a tidal channel is studied with the use of an idealized morphodynamic model. The latter is based on depth-averaged equations for the tidal flow over a sandy bottom. The model considers phenomena on spatial scales of the order of the tidal excursion length. Transport of sediment mainly takes place as suspended load. The reference state of this model is characterized by a spatially uniform M2 tidal current over a fixed horizontal bed. The temporal evolution of deviations from this reference state is governed by amplitude equations: these are a set of non-linear equations that describe the temporal evolution of bed forms. These equations are used to obtain new morphodynamic equilibria which may be either static or time-periodic. Several of these bottom profiles show strong similarity with the tidal bars that are observed in natural estuaries. The dependence of the equilibrium solutions on the value of bottom friction and channel width is investigated systematically. For narrow channels (width small compared to the tidal excursion length) stable static equilibria exist if bottom friction is slightly larger than rcr. For channel widths more comparable to the tidal excursion length, multiple stable steady states may exist for bottom friction parameter values below rcr. Regardless of channel width, stable time-periodic equilibria seem to emerge as the bottom friction is increased.Responsible Editor: Jens Kappenberg 相似文献
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Several theoretical, empirical and semi-empirical methods are available in the literature to predict settlement of drilled
shafts in sandy soils. In the Arabian Gulf countries, specifically in the United Arab Emirates, equations and procedure from
the rest of the world are being used in analysis and design of drilled shafts without proper validation. It is the aim of
this study to assess the applicability and evaluate the accuracy of two well known, and commonly used methods for pile prediction
in the United Arab Emirates (UAE), namely Vesic (1977) and Poulos (1979), via comparison with data from field pile load tests
conducted on shafts drilled in the region. Some of these tests were conducted for the purpose of this study, while others
were made available through the courtesy of International Piling Contractors who are active in the region (e.g. Bauer International
and Swiss Borings). Pile load test data were analyzed to back-calculate the model parameters related to settlement under different
loading stages. Geological data and soil properties were obtained from studies conducted at the relevant sites. An effort
is made to correlate soil properties with the prediction models. Statistical analysis is conducted to assess the accuracy
of the results obtained from the two methods at different stages of loading via those obtained from pile load tests. Moreover,
a detailed parametric study is conducted to assess the effect of the related parameters on the predicted pile settlement and
the estimated settlement at different stages of loading. The study concluded with a recommendation of the most appropriate
models and procedures to be followed for predicting the settlement of drilled shafts in the UAE, together with useful charts
and correlation relations. Results showed that settlement values predicted by Vesic (1977) and Poulos (1979) overestimates
the true values.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献