Physico-mechanical properties of soft clay in Zhuhai Region have been achieved according to the data collected from the in-situ tests. Results show that the characteristics of soft soil in Zhuhai Region are with higher water content，higher compressive property，and lower load capacity. The soils have the strongly structural characteristics and preconsolidation characteristics too. Based on a detailed investigation into the previous engineering construction in Zhuhai Region and the experience with both successful and failure results，an overview is withdrawn on the soft soil treatment，soft soil foundation pit，pile foundation and other geotechnical engineering issues.

The geological disaster evaluation is performed through the research on the distribution of geological environment conditions，the effecting factors of the geological disasters，time history，present condition and future potential geological disasters. In order to prevent and minimize the potential geological disaster，the distribution of geological disasters，which have already taken place，should be evaluated. The evaluation results can predict the occurrence of the geological disasters and avoid or reduce the death，injury and property loss. If the geological disasters are properly predicted，the development of the social performance，economical performance and the environment performance are coordinated and developed.

Shenzhen City is a seashore city with axial ridge and low mountain physiognomy to seashore plain from the North to the South. The geological characteristics are of complicate geology，uneven stratum，crushed rock，strong rainfall，ample groundwater and strong tectonism. There are certain slope instability types in Shenzhen City：landslide and collapse arising in shallow loose soil，slope sliding along the consequent faults in soft metamorphosed rock and in mixed rock and sliding being caused by the tectonic hard core of granite. The principles of those diseases can be categorized as follows：(1) most of sliding arises from the correlated impact of rainfall and groundwater；(2) instability is often developed along the south of ridge with the strike direction of EW；(3) landslides and collapse are often developed in soft rock and cracked rock，but landslip and rock fall often in hard rock；and (4) Shenzhen large fault has strong impact on the slope instability，on whose upper bed more instability disasters are developed and vice versa. More instability disasters are developed strongly on the zone of the main NE strike fault intersected with other faults. Though more preventions and new technologies are adopted in slope instability treatment，the progresses of Shenzhen slope instability prevention and control should proceed as follows：(1) the law of “geology is foundation”should be carried out；(2) the new techniques should be adopted；(3) supervision should be enhanced；(4) more attention to should be paid to the research of the effect of treatment measures；and (5) the standards of slope instability prevention and control should be established.

The triaxial compressive response depiction method of rocks and anisotropy response depiction method of soils are proposed based on the disturbed state concept(DSC). DSC defines the response of material that is subjected to loading is a weighted average value of two reference response states. The actual response is composed of relative intact state response and fully adjusted state response with a disturbance factor as the weighted factor. DSC presents an average course，but the reference state responses are not displayed deteriorating course. On the triaxial compressive response depiction method of rock，DSC gives qualified fitness of stress-strain softening phase of red sandstone under regular triaxial compressive test. Steady entire phase of the stress-strain curve shows the ability of RMT–150B rock experiment instrument. Stress-strain relationship curve is described after the compact point. Disturbance factor parameters change with confining pressure value. On the anisotropy response depiction method of soil，anisotropic disturbance factor is superposed to isotropic results obtained from hierarchical single surface(HISS) model utility to show stress anisotropic characteristics of the material. The orientation of disturbance factor vector is the same as that of vector of material unit stress. The finite element method process of stress anisotropic DSC based on HISS model is presented，including detailed steps of loading and unloading certification，initial value confirmation and hardening floating rectification. Two examples prove the effectiveness of the introduced methods.

Method of settlement after construction is often used to decide unloading time. To avoid the confusion that residual settlement is regarded as settlement after construction，two equations between the residual settlement and settlement after construction are given based on the analysis of their difference. The final settlement in the method of settlement after construction is corresponding to the design load. For surcharge and undercharge conditions，the equation between final settlement and filling height should be achieved through monitoring results. The final settlement responding to the design load should be got with the above equation. For multi-layer ground，the presented method often leads to early unloading and over settlement after construction. For this kind of ground，the settlement after construction of each layer should be analyzed；and the total settlement after construction can be achieved by superimposing the settlement after construction of each layer.

The equilibrium between gravity of the upper impermeable stratum and water pressure is a common calculation method for anti-uprush of foundation pit. In case the effective unit weight of upper stratum is less than the seepage force，its low strength and high permeability will lead to the instability of the bottom of the foundation pit，and the calculation method equilibrating between effective unit weight and seepage force should be adopted in this case. The two kinds of the calculation methods are confusable in practical application. Similarities and differences between the methods，such as the expression，principium，safety coefficient and application，are analyzed，and the principles to choose the methods are discussed. The methods are also applied to a engineering project，and the achieved results indicate that the reasonable choice of calculation methods of anti-floating for foundation pit is important，and some valuable conclusions are drawn.

Based on several traditional plugging methods in pore water pressure measurement with technical difficulties，a new plugging technique is presented，and some in-situ contrast tests in a soft soil engineering consolidated by vacuum preloading in Guangzhou Nansha was performed. Test results show that it is difficult to plug the hole among the piezometers using the traditional hole-breakdown method because the piezometers will not be separated and differences of the pore water pressure in different depths will be the same，which will cause great measure errors. The newly employed plugging device can effectively be separated，and the differences of the pore water pressure in the different depths will not be same. So the test results with more accuracy can be obtained，and it is convenient for construction and the positions of piezometers can be accurately controlled. The influences of variations of the settlement and groundwater level to pore water pressure are analyzed. The greater variations of the settlement and groundwater level are，the greater variation values of pore water pressure are. Test results also show that the variable values of pore water pressure caused by the variations of settlement and groundwater level can reach to 20 kPa，which should be deducted when analyzing the dissipation of the pore water pressure or the distribution mode of excess pore water pressure.

Based on the successful examples of sealing water gushing of dissolved cave located in a limestone area，the reasons of gushing，the confirm of cave¢s position，cave design scheme and implement，examining effects and the summarized experiences are presented. The practical examples of grouting technique for treating gushing dissolved cave in limestone area are introduced by analyzing of the formation mechanism of the cave，theoretical analysis，construction technique scheme，and construction management planning used in the course of sealing the cave. The achieved results can provide references to other similar types of anti-leaping and basement reinforcement.

In order to determine the stress state at underground power house and pressure tunnel of Shenzhen pumped storage plant，in-situ stress measurements by hydro-fracturing method and overcoming method are carried out for comparison. Also，the stress distribution in the whole rock mass including the major project locations is obtained through FEM regression analysis. Finally，the selection of underground power house axis and the lining design scheme for the pressure tunnel are discussed based on the in-situ stress.

The slity soil on the modern Yellow River Delta is the fine sediment which has been rapidly accumulated since the Yellow River divagated into Bohai Sea in 1855. The coverage area is about 5 000 km2. It almost covers Shengli Oil Field in Dongying City，Shandong Province. Four groups of site contrast tests are chosen to conduct the systematic site soil tests including the plate load test，spire plate load test，flat dilatometer test，standard penetration test and static cone penetration test. The characteristic values of the bearing capacity of the fine sediment that has been rapidly accumulated recently in entrance of Yellow River are studied according to the analysis of the site test and the laboratory test. The difference between the characteristic values of the bearing capacities that are confirmed by different methods is systematically contrasted. Moreover，the regression equations between specific penetration resistance Ps，blow counts of standard penetration test N，water content w and porosity ration e and the characteristic value of bearing capacity fk are built according to the bearing capacity that is confirmed by the plate load test. The research can provide scientific references to determine the characteristic value of the bearing capacity of the slity soil on the modern Yellow River Delta.