双参数地基层合板的静、动力分析

抛弃了人为的应力和位移假设,直接从三维弹性动力方程出发,建立了正交异性地基板的状态方程,同时导出了双参数地基上四边简支层合板静力问题的解析式和动力问题的频率方程。

临海地区地基层及地库外墙防水体系施工方法

针对地下室墙身与底面长期埋在潮湿的土中或浸在地下水中容易出现结构的问题,尤其在临海地区的地基层及地库外墙必须做防潮或防水处理,论文提出了一种外防水体系的施工方法,此防水体系适用于地库及不允许进水的地下构筑物,有效地阻挡地下水渗入结构,不仅可减少地下水导致结构问题引起的维修,而且能有效延长结构混凝土寿命。

商业经营责任制的几个认识问题

在党的十一届三中全会提出改革我国经济管理体制,扩大企业经营管理自主权以后,各地基层商业企业相继进行了扩大自主权的试点工作。一九八一年以来,在农业生产责任制的影响和带动下,又逐步试行了各种不同形式的经营责任制,这是商业企业经济管理形式的重大改革。与任何事物一样,在开始阶段必然会迂到各种各样的思想认识上和具体实践上的一系列问题,需要不断探索和研究,本文仅就其中几个认识问题谈点个人的粗浅看法。

Analysis of one-dimensional rheological consolidation of double-layered soil with fractional derivative Merchant model and non-Darcian flow described by non-Newtonian index

To further investigate the one-dimensional(1D)rheological consolidation mechanism of double-layered soil,the fractional derivative Merchant model(FDMM)and the non-Darcian flow model with the non-Newtonian index are respectively introduced to describe the deformation of viscoelastic soil and the flow of pore water in the process of consolidation.Accordingly,an 1D rheological consolidation equation of double-layered soil is obtained,and its numerical analysis is performed by the implicit finite difference method.In order to verify its validity,the numerical solutions by the present method for some simplified cases are compared with the results in the related literature.Then,the influence of the revelent parameters on the rheological consolidation of double-layered soil are investigated.Numerical results indicate that the parameters of non-Darcian flow and FDMM of the first soil layer greatly influence the consolidation rate of double-layered soil.As the decrease of relative compressibility or the increase of relative permeability between the lower soil and the upper soil,the dissipation rate of excess pore water pressure and the settlement rate of the ground will be accelerated.Increasing the relative thickness of soil layer with high permeability or low compressibility will also accelerate the consolidation rate of double-layered soil.

Longitudinal dynamic response of pile in layered soil based on virtual soil pile model

Taking the effect of finite soil layers below pile end into account,the longitudinal dynamic response of pile undergoing dynamic loading in layered soil was theoretically investigated.Firstly,finite soil layers below pile end are modeled as virtual soil pile whose cross-section area is the same as that of the pile and the soil layers surrounding the pile are described by the plane strain model.Then,by virtue of Laplace transform and impedance function transfer method,the analytical solution of longitudinal dynamic response at the pile head in frequency domain is yielded.Also,the semi-analytical solution in time domain undergoing half-cycle sine pulse at the pile head is obtained by means of inverse Laplace transform.Based on these solutions,a parametric study is conducted to analyze emphatically the effects of parameters of soil below pile end on velocity admittance and reflected wave signals at the pile head.Additionally,a comparison with other models with different supporting conditions from soil below pile end is performed to verify the model presented.

Solution of a rigid disk on saturated soil considering consolidation and rheology

The problem of a rigid disk acting with normal force on saturated soil was studied using Biot consolidation theory and integral equation method and the Merchant model to describe the saturated soil rheology. Using integral transform techniques, general solutions of Biot consolidation functions and the dual integral equations of a rigid disk on saturated soil were established based on the boundary conditions. These equations can be simplified using Laplace-Hankel and Abel transform methods. The numerical solutions of the integral equations, and the corresponding inversion transform were used to obtain the settlement and contact stresses of the rigid disk. Numerical examples showed that the soil settlement is small if only consolidation is considered, so the soil rheology must be taken into account to calculate the soil settlement. Numerical solution of Hankel inverse transform is also given in this paper.

Protection Measures for Buildings Based on Coordinating Action Theory of Ground, Foundation and Structure

Based on the theory of coordinating action of building ground, foundation and structure, this paper presents a modified method for calculating additional stresses on buildings in mining areas by considering the joint effect of cur- vature deformation and horizontal deformation on buildings. It points out that for buildings over the coal pillar, it is ad- visable to soften the intermediate ground of buildings when they are affected by mining. For buildings over the goaf, it is preferable to soften the ground at both ends of buildings. In order to enhance the ability of a building to resist tensile deformation, the key measure is to reinforce the bottom foundation of the building. In addition, the concept of “angle of break of building” is proposed. It is because of this angle that the protecting coal pillar is left, which is a better solution than prevailing solutions The findings provide a more scientific basis for mining under buildings.

Control over Surrounding Rocks Deformation of Soft Floor and Whole-Coal Gateways with Trapezoidal Supports

In Gengcun Colliery, Yima Coal Group Co. Ltd.the characteristics of the gateways of thick coal seam and the coal seam is with fully mechanized sublevel caving mining are that the thickness of roof coal seam of gateways is larger, their surrounding rocks are the whole-coal mass and the coal seam is prone to Spontaneous Combustion. With the natural equilibrium arch theory, the reasonable adjacent distance of No.11 mine-type metal supports was calculated in trapezoidal gateways based on these characteristics. Then, in-situ supporting experiments were carried out. The results indicate that under the action of virgin rock stress, the width of broken rocks zone of surrounding rocks is 1.7–2.0 m in return heading and 1.1–1.3 m in going headway. And their surrounding rocks belong to the Ⅳ-type soften rock and the Ⅲ-type common surrounding rock respectively. Therefore, under the movable abutment pressure, the gateways deformation is serious. It is suggested that the designed gateways have to use pre-broadened cross section to suit their deformation. At the same time, the accumulated water on gateway floor must be drained in time. These measures were taken in the 1302 and 1304 coal faces in Gengcun Colliery, and the satisfactory results have been obtained.

Skewness of subsurface ocean temperature in the equatorial Pacific based on assimilated data

The skewness of subsurface temperature anomaly in the equatorial Pacific Ocean shows a significant asymmetry between the east and west. A positive temperature skewness appears in the equatorial eastern Pacific, while the temperature skewness in the western and central Pacific is primarily negative. There is also an asymmetry of the temperature skewness above and below the climatological mean therrnocline in the central and western Pacific. A positive skewness appears below the thermocline, but the skewness is negative above the thermocline. The distinctive vertical asymmetry of the temperature skewness is argued to be attributed to the asymmetric temperature response to upward and downward thermocline displacement in the presence of the observed upper-ocean vertical thermal structure. Because of positive （negative） second derivative of temperature with respect to depth below （above） the thermocline, an upward and a downward shift of the thermocline with equal displacement would lead to a negative temperature skewness above the thermocline but a positive skewness below the thermocline. In the far eastern equatorial Pacific, the thermocline is close to the base of the mixed layer, the shape of the upper-ocean vertical temperature profile cannot be kept. Positive skewness appears in both below the thermocline and above the thermocline in the far eastern basin. Over the central and eastern Pacific, the anomalies of the subsurface waters tend to entrain into the surface mixed layer （by climatological mean upwelling） and then affect the SST. Hence, the positive （negative） subsurface skewness in the far eastern （central） Pacific may favor positive （negative） SST skewness, which is consistent with the observational fact that more La Nina （EI Nino） occur in the central （eastern） Pacific. The present result implies a possible new paradigm for EI Nino and La Nina amplitude asymmetry in the eastern Pacific.

Study on one-dimensional consolidation of soil under cyclic loading and with varied compressibility

This paper presents a semi-analytical method to solve one dimensional consolidation problem by taking consideration of varied compressibility of soil under cyclic loading. In the method, soil stratum is divided equally into n layers while load and consolidation time are also divided into small parts and time intervals accordingly. The problem of one-dimensional consolidation of soil stratum under cyclic loading can then be dealt with at each time interval as one-dimensional linear consolidation of multi-layered soils under constant loading. The compression or rebounding of each soil layer can be judged by the effective stress of the layer. When the effective stress is larger than that in the last time interval, the soil layer is compressed, and when it is smaller, the soil layer rebounds. Thus, appropriate compressibility can be chosen and the consolidation of the layered system can be analyzed by the available analytical linear consolidation theory. Based on the semi-analytical method, a computer program was developed and the behavior of one-dimensional consolidation of soil with varied compressibility under cyclic loading was investigated, and compared with the available consolidation theory which takes no consideration of varied compressibility of soil under cyclic loading. The results showed that by taking the variable compressibility into account, the rate of consolidation of soil was greater than the one predicted by conventional consolidation theory.

Tunnelling through weak and fragile rocks of Himalayas

A considerable amount of tunnelling has been going on in India for various projects such as hydroelectric power, irrigation, roads and railways. Most of these projects are located in Himalayas, far away from the urban areas. Tunnelling through weak and jointed rock masses such as the one in the Himalayas is a challenging task for the planners, designers, engineers and geologists because of high overburden, thickly vegetated surface, weak, poor and fragile rocks and highly varying geology with the presence of numerous small and big shear zones, faults, etc. Due to these reasons, various tunnelling problems have been faced in the past and are still being encountered. Failures and the problems may be regarded as challenges and opportunities for generating new knowledge base and thereby increasing self-reliance in tunnelling. The experiences of Himalayan tunnelling through weak and fragile rocks covering varying and mixed geology, understanding on tunnelling in squeezing ground conditions and applicability of TBM in Himalayas are presented. It has also been highlighted that the probe holes planning, drilling and monitoring shall be followed seriously to reduce the geological surprises.

Elastoplastic numerical analysis of layered soil foundation under the rectangular shallow footing subjected to vertical load

Finite and infinite coupled element method was used to analyze the strength and deformation in layered soil foundation which was under the rectangular shallow footing subjected to vertical loads. In the numerical analysis, the footing was assumed to be elastic; the soil was assumed to be elastoplastic and the Drucker-Prager constitutive model was applied to describe its mechanic behavior. Corresponding program was employed to compute six kinds of layered soil foundations constituted by different soil layers. The conclusions which are useful in the theory and practice were made according to the analysis of the computation results.

Assessment of Water Losses from Badovc Lake, Kosovo： Hydrochemical Implications

This paper aims to quantitatively assess water losses of Badovc Lake-Kosovo based on both water balance of the lake and water hydrochemistry. This attempt was strongly prompt by both the importance of this lake for water supply of Prishtina city and the lack of water. According to lake water balance, a water loss of 3,738,905 m^3 and 1,722,552 m^3 for the hydrologic year 2014 and the period January-May （2015） was evaluated. These consistent data favour the opinion that a continuous groundwater outflow from the lake is present and it is conditioned by the intensively developed fracture system in the lake basement formations. This was also supported by the chemical data （chloride, sulphate, hardness and electric conductivity etc.） of the water. Water from the leakages on the right side of the dam shows the same chemical signature as the water from the lake. Whereas, water from the piezometer, monitoring well and the gallery of Hajvalia mine show similar values with those of the water from the lake. The calculations of the chloride mass balance showed that the fractions of lake and rainfall waters in the water mixture of Hajvalia mine were 67% and 33% respectively.

Reinjection Tests in Bedrock Geothermal Reservoir of Tianjin

By the end of 2002, there are about 219 production wells (including 12 reinjection wells) in Tianjin. The annual production rate is 1.5×10 7 m 3 and the reinjection rate is 1.66×10 6 m 3. The main side effect anticipated from reinjection is the cooling of the reservoir. It is necessary to estimate the thermal breakthrough time in different distances between injection production wells. This paper describes the 2 D mass and heat transfer in the heterogeneous fractured rocks. The equations that arise for each grid block must be linearized. The main reinjection model is simulated by a program of the TOUGH2 to analyze the change of the temperature field and predict the pressure and heat break through. The tracer test is very important for understanding the transportation pathway and transport channel/space in the doublet system, and estimating the possible cooling resulted from the injection processes.

Dynamic Responses Analysis of a Building Structure Subjected to Ground Shock from a Tunnel Explosion

Dynamic responses of a multi-storey building without or with a sliding base-isolation device for ground shock induced by an in-tunnel explosion are numerically analyzed. The effect of an adjacent tunnel in between the building and the explosion tunnel, which affects ground shock propagation , is considered in the analysis. Different modeling methods, such as the eight-node equal-parametric finite element and mass-lumped system, are used to establish the coupling model consisting of the two adjacent tunnels, the surrounding soil medium with the Lysmer viscous boundary condition, and the multi-storey building with or without the sliding base-isolation device. In numerical calculations , a continuous friction model, which is different from the traditional Coulomb friction model, is adopted to improve the computational efficiency and reduce the accumulated errors. Some example analyses are subsequently performed to study the response characteristics of the building and the sliding base-isolation device to ground shock. The effect of the adjacent tunnel in between the building and the explosion tunnel on the ground shock wave propagation is also investigated. The final conclusions based on the numerical results will provide some guidance in engineering practice.

System of Combined Foundation for Tall Buildings

Location of the heavily loaded building on the ground of the small load capacity requires application of the appropriate foundation structure. The required foundation system is most often deep, it is expensive and its cost increases significantly when the building is located in earthquake area or in mining damage sector. The proposed structural system of the combined foundation makes possible to design and to construct a very stable and relative inexpensive foundation structure, which can obtain an extremely large horizontal surface and which can be placed not deeply beneath the terrain level. It can be a very solid support structure for a tall building placed on very weak subsoil and at the same time located in seismic area. This system can be applied not only for new buildings but it can be used for the existing buildings and moreover for straighten of the inclined objects. Due to special arrangement of component parts the combined foundation possesses inherent features of a vibration damper, what is highly desirable if buildings have to be located in earthquake areas. When the aboveground storeys structure has some similar patterns with structural form of the combined foundation then the structural system of the whole building obtains coherent structural characteristics and it is called the combined structural system of the tall building. Suitable application of this system makes possible to design high-rise buildings having interesting and unique architectonic forms, what is presented on a selected example.

Railway Foundation Design Principles

There are a number of design procedures which have been developed to determine the appropriate thickness of trackbed layers on a railway track in order to reduce train induced stresses to an acceptable level thus ensuring that subgrade failure does not occur prematurely. This paper briefly describes four such procedures and compares the thickness of trackbed layers proposed by each for a number of hypothetical situations. To demonstrate further the suitability of each procedure, two existing sites in the UK are analysed and the trackbed layer thickness given by each procedure is then compared. The research shows that the procedures do not give consistent results. Subsequently it is suggested that it is important to consider other aspects in addition to the prescription of a suitable thickness of trackbed layers in any new build, renewal or remediation scheme.

GiT-based structural geologic feature analysis of the southern segment of Longmenshan fault zone for earthquake evidence

The Longmenshan fault is a thrust fault which runs along the base of the Longmen Mountains in Siehuan province, southwestern China. The southern segment of the fault had two distinct responses to the Ms 8 Wenehuan and Ms 7 Lushan earthquakes. This study determines characteristics of the structural geology of the Longmenshan fault to evaluate how it influenced the two aforementioned earthquakes. This research was done within a Geo- information Technologies （GiT） environment based on multi-source remote sensing and crustal movement data extracted from the Global Positioning System （GPS）. The spatial distribution of the southern segment of the Longmenshan fault zone was comprehensively analyzed to study both earthquakes. The study revealed that the Wenehuan and Lushan earthquakes occurred on two relatively independent faults. In addition, there was a nearly constant-velocity crustal movement zone between the two epicenters that probably had a compressive stress with slow motion. Furthermore, the central fault and a mountain back fault gradually merged from north to south. The Lushan earthquake of the Wenchuan earthquake. was not an affershock The research showed that fault zones within 30-50 km of State Highway 318 are intensive and complex. In addition, crustal movement velocity decreased rapidly, with a strong multi-directional shear zone. Thus, activity in that zone was likely stronger than in the northern part over the medium to long term.