郑州黄河岸边开采地下水对大堤稳定性影响

通过对郑州市黄河大堤一线土体的沉降，压密固结，饱水砂土的地震液化研究，认为黄河大堤附近浅层地下水开采后所诱发的地面沉降，固结过程，不会对大堤造成危害，而饱水砂土的水位降低，还会减轻或消除地震时液化砂土现象，对大堤的稳定性有利。     

评定渗流管涌公式

根据工程实际问题，推导了在江河堤围、深基坑开挖和矿山法地铁开挖三种情况下的评定渗流管涌公式，并指出应根据不同情况选用不同的评定渗流管涌公式，及使用中必须考虑的问题。     

南边界强迫的非线性临界层与副高的形成、维持和振荡

用非线性准地转正压涡度方程模式，在南边界取定常强迫波，采用４种方案模拟了非线性临界层及其上激发的Ｋｅｌｖｉｎ猫眼，以确定热带的定常强迫对副高的形成、维持和振荡的影响。结果表明，南边界定常强迫仍在非线性临界层内激发行星尺度的准定常反气旋的Ｋｅｌｖｉｎ猫眼流场，猫眼的移动、强度和形状变化与夏季副高比较相似．而北边界定常强迫所得结果与夏季副高差异较大。因此，南边界所激发的非线性临界层上的Ｋｅｌｖｉｎ猫眼可能是夏季副高形成、维持和振荡的一种更为重要的新物理机制。文中还提出准定常行星波穿越副热带的非线性临界层的物理机制。     

论青藏高原隆起作用于大气的临界高度

在以前工作的基础上，从大气动力学、热力学及气候学的角度，进一步论证了在青茂高原隆起过程中存在一个临界高度ｈｃ（－１．５－２ｋｍ）。当高原隆起突破这一临界高度时才开始对大气产生强烈的作用，从而造成大气环流、大气热力结构、亚洲区域以及全球气候等一系列巨大转变。     

Modelling of ground motion in the vicinity of massive structures

A two-dimensional elastic Chebyshev spectral element method (SPEM) is used to model the seismic wavefield within a massive structure and in its vicinity. We consider 2-D models where a linear elastic structure, with quadrangular cross-section, resting on an elastic homogeneous half-space, is impinged upon by the waves generated by a surface impulse at some distance. The scattering of Rayleigh waves and the response of the structure are extensively analysed in a parametric way, varying size, mechanical parameters and shape of the load. Some of the models considered are representative of embankments and earth dams. The simulation shows that some models resonate, storing part of the incoming energy. With realistic parameters, the lowest resonance frequency is due to pure shear deformation and is controlled by the shear velocity and height of the load. Flexural modes are excited only at higher frequencies. The acceleration at the top of the structure may be five/seven times higher than at the base, depending on the mass of the structure. The gradual release of trapped energy produces a ground roll lasting several seconds after the wave front has passed. The ground-roll amplitude depends on the sturcture's mass and can be as large as 30% of the peak acceleration. Outside resonance conditions, the ground motion is almost unaffected by the presence of the artefact; the horizontal motion on top of it is nearly twice the motion at ground level. Similar results should be expected when the incident field is an upcoming shear wave. A qualitative discussion shows that the presence of anelastic attenuation in the embankment does not significantly alter the preceding conclusions, unless it is of very low values (e.g. Q < 15).The modelling results that we discuss indicate that the soil-structure interaction may substantially alter the ‘free-field’ ground motion. From a practical point of view, the main conclusions are: (1) careful analysis is necessary when interpreting seismic records collected in the vicinity of large artefacts; (2) seismic hazard at a site may depend on the presence of man-made structures such as embankments, dams, tall and massive buildings.     

Investigation on the geological and geotechnical factors leading to a major slope failure at a selected site on a Jordanian highway

During and after the very wet 1991/1992 winter experienced in Jordan, significant slope failures occurred along several sections of the new Irbid-Amman highway in Jordan. The topography over most of the route is hilly, and significant amounts of cut and fill were used to construct the highway. One such slope failure lies at 44+800 km on the highway south of Jerash City at a distance of about 5.0 km from Wadi Zerqa bridge. A landslide occurred downslope of the highway embankment resulting in a collapse of the most of the gabbion wall supporting the embankment. This paper deals with the overall stability of the slope at 44+800 km. It presents the geological and geotechnical studies carried out at this site, identifies the causes and mechanism of instability, and presents appropriate remedial measures. The study concluded that the landslide movement occurred within the colluvium material. It resulted primarily from excess piezometric pressures generated within the slope as a direct consequence of inadequate drainage. It is recommended to reconstruct the entire gabbion wall with its foundation seated on the sandstone that underlies the colluvium and to install a surface drainage system at the site.     

单个粘土体裂缝中水流规律的研究

通过模型实验,研究粘土体裂缝中的水流规律,提出了临界水位上升速度的概念。水位上升速度大于临界值时,裂缝中水流量增加,反之则减少。裂缝水流量与水位不呈正比关系。指出粘土裂缝中最大水流量要比相同条件下基岩裂缝水流量小30—40倍。随着水流运动的延续,水流量将逐渐变小。在水流作用下,粘土裂缝宽度将变窄3.0—4.0cm,裂缝深度也大幅度变浅到裂缝水深的50％以上。     

Estimation of abl Parameters Using the Vertical Velocity Measurements of an Acoustic Sounder

The friction velocity, the surface heat flux and the height of the Atmospheric Boundary Layer (ABL) are important parameters. In this work, vertical velocity variance ( _w ² ) and wind velocity structure parameter (C _v ² ) profiles estimated by acoustic sounder measurements are used, along with similarity relations, to estimate these parameters in the unstable Atmospheric Boundary Layer and the friction velocity in the stable one. The data were collected by two acoustic sounders with different height range and resolution under various atmospheric conditions (stability) and at two experimental sites in different terrain. The C _v ² profiles are estimated using gate difference of the vertical velocity measurements and the assumption of local isotropy. The vertical velocity data are corrected for the significant effects of noisy measurements and sampling volume averaging on the _w ² and C _v ² estimations using original techniques that are presented in this work. The results of the similarity method using acoustic sounder data are compared against estimates of the corresponding atmospheric parameters obtained from direct measurements. The comparison confirms the ability of the method to provide reasonably accurate estimates of these parameters especially in the middle of the day.     

NON-LINEAR CRITICAL LAYER IN EL NINO AND LA NINA YEARS AND FORMATION, MAINTENTENANCE AND OSCILLATION OF THE SUBTROPICAL HIGH

Monthly mean zonal wind data from the European Center for Medium-range Weather Forecasting(ECMWF)for December 1982, April 1983, October 1984 and ApriI 1985 are used in numerical integration as thebasic flow in a non-linear critical-layer model. The subtropical high is extensive and limited in number if simulated with the basic now in December 1982 and April 1983. It consists of 2 to 3 cells that move westward at alloscillatory periods of 1～2 months. The subtropical high, simulated with the basic flow in October 1984 and April1 985. is weak and small in coverage, or distributed in strips that contain up to 4 cells. The high. merged or spillover a short time. is moving westward. The years 1982 ～1983 are a process of EI Niño while the years 1984-1985one of La Niña. lt is known from the chart of energy flux that it oscillates by a much larger amplitude and longerperiod in the EI Niño year than in the La Niña year. All the results above have indicated that the basic flow in the EI Niño year is enhancing the subtropical high lagging by about 4 months and that in the La Niña year is decay'ing it. It is consiStent with the well-known observational fact that the SSTA in the equatorial eastern Pacitlc ispositively correlated with the extent and intensity of the subtropical high in west Pacific lagging by 1～2 seasons.The result is also important for further study of the formation, maintenance and oscillation of the subtropicalhigh.     

Sea surface height and transport stream function of the South China Sea from a variable-grid global ocean circulation model

The study on the South China Sea (SCS) circulation has a history of more than 40 years. Nevertheless, the SCS circulation is not fully understood compared with the Bohai Sea, Yellow Sea and East China Sea (ECS). Many numerical studies on the SCS circulati…