This paper introduces comprehensive research on stability of a large –span cavern ,including a lot of in –situ tests on rock ,the measurements of initial stress field ,applications of seismic velocity method and so on .Also it introduces numerical modeling with the finite element method .Finally , some significant conclusions for selecting the site and line of the large span cavern as well as for design and construction of the support are given .

At first ,this paper summarizes the basic contents and theoretical state of soil elastic-plastic constitutive relationship used for blast wave calculations .In particular ,it has given more detailed account of the relatively comprehensive soil hardening plastic model-cap model model which has been developed in the world today .then ,we present a complete preliminary procedure of how to make cap model experiments in a large stress range by the use of our current experimental devices in our country .this is the most important content of the present paper .

In this paper one type of joint element –six –node isoparametric joint element for 2-D problem is introduced .The corresponding formulae used for finite element analysis has been derived and given here . Using the program written by us several examples of calculations and comparisons have been done .The results show that such a joint element model can eb used successfully to simulate the joints ,intercalations and structural planes in rock masses and can give a more accurate results than that of the joint element ordinary used .Especially it has the obvious advantages when using it for representing the nonflat joints and wave –like form weak intercalations. A sixteen –node isoparametric joint element model for 3-Dproblem and the corresponding formulate are also given in the paper .

The engineering classification of rock masses is one of the basic problems in rock mechanics .The main purpose of engineering classification of rock masses is comprehensively to evaluate rock masses ,to divide the rock masses into several proper classes and to offer guantitative data for engineering design .therefore engineering classification of rock masses is very important for engineering practice and aroused a great interest to the investigators of rock mechanics .On the basis of Bieniawski’s geomechanics classification of rock masses , a new method of engineering classification of rock masses has been proposed by means of the theory of modern fuzzy mathematics .In this classification the rock masses are evaluated on the basis of six parameters :the uniaxial compressive strength of the rock material drill core quality RQD, spacing ,orientation and condition of joints ,and ground water inflow. The rating for each parameter is determined and total rating for rock mass is specified by the method of weighted average .The rating and the weight for each parameter were considered as fuzzy variables . Therefore not only the total rating but also varying Range of total rating(or pthe membership of total rating ) are given .The randomly varying state of in situ rock masses can be described by this method of classification so that the result of comprehensively evaluating is more accurate than others . In additional, an accurate and simple evaluating method that is suitable for the engineers has been given .

This paper presents a semi-graphic and semi-analytical method for determing the stability coefficient of the slope sliding mass ,instead of slices and accuracy methods under the simplest condition .The accuracy of determined stability coefficient by the introduced method may fully meet with the demand and the calculation amount is less . The method is essentially once-solution for the total a mount of silding body weight (or area ),and total amount being divided into tangential and radial components ,then the stability coefficient calculated .For comparison ,the geometrical parameters and strength indexes (c, φ)of the same slope are applied for calculations by the method slices (in 5 blocks and blocks ).accuracy method and the semi-graphic and semi-analytical method .The result shows kaccuracy > kgraphic > k10 > k5 ,which indicates the applicability and its accuracy . This method is suitable for stability coefficient calculation of the soil slope and rock slope of much fissured and cataclastic media in the simplest conditions conforming to the assumption .

The long-term creep test were conducted for the undisturbed clay samples of shanghai at the depth from 13m-27m.The viscoelastic constants of the shanghai clay were determined according to the method proposed by gibzon and Lo. The magnitude of primary and secondary consolidation were calculated by the analogical method of E.H.Lee. The calculated results were compared with the results of test .A fairly good agreement was found between these two results .

This paper describes a high input impedance preamplifier ,a main amplifier ,including its specification and the circuits theories .An acceleration measurement system consist of the piezoelectric acceleration 、preamplifier、cable 、main amplifier and oscilloscope for measureing the acceleration of vibration due to explosion .The features of the system are :1.good stability ,2.small zero shift ,3.The preamplifier is a new circuit which consists of four transistors 3DG6C,3DG4E. Its input impedance is as high as 1500MΩ and is able to undertake a high instantaneous impulse voltage ,4.There is no power supply set near the preamplifier .The signal transmiting cable is also the power supply cable so that the transmiting characteristic is very well .when the cable length is varied from 1 meter to 1000 meters ,the frequency response of system will not change .The decrement of output amplitude is less than 6% etc.