The relationships between strength indexes c, ? and dry density ，degree of saturation sr，water content ?, strength and swelling pressure p of expansive soil are researched. The results show that the relationship between c，tan? and , sr, ? are similar to that of between swelling pressure p and , sr, ?；the strength of expansive soil under any state can be represented both by strength under saturated state and addition strength produced by suction; and the latter can be represented by swelling pressure of soil in various states.

Aiming at acknowledging the slaking of expansive red sandstones in Hongshanyao hydrojunction project, by using the scanning electron microscope, X-ray diffractometer and rock mechanics rigidity electroplating servo testing system(RMTS815.03) in the tests, three different weathering degree swelling sandstones with properties of slight swelling, softening and easily weathering are observed in the process of slaking and mechanics of slaking are analyzed. Finally the slaking of red sandstone is different from swelling and fissuring essentially. Experimental results indicate that: (1)The compressive strength of the moderate weathering red sandstone, when dried, is 5.85MPa, whereas is 0.2MPa when saturated. The rock self strength is decreased with the increasing of water content, which is in possession of the serious softening effect; (2)The slaking of the expansive rock is strengthened with the decreasing of cementation coefficient, which is irrelevant to the weathering degrees of red sandstone (the depth of embedding); (3)These studies are provided the theory guiding to settle the slope topsoil slip of Hongshanyao hydrojunction project and also could be used in other related domain.

On the basis of coulomb’s concept that the earth pressure against the back of a retaining wall is due to the thrust exerted by a sliding wedge of soil between the back of the wall and a plane which passes through the bottom edge of the wall and has an inclination of , the differential equations of first order are set up by considering the equilibrium of the forces and the moments on an element of the wedge. The lateral coefficient of earth pressure, the unit earth pressure, the resultant force of earth pressure and the application point of the resultant force are obtained. The effects of the internal frictional angle of backfill and the frictional angle between the wall back and the backfill on the lateral coefficient of earth pressure, the unit earth pressure, the resultant force of earth pressure, the application point of the resultant force and the overturning stability of a retaining wall are investigated.

A new method to calculate the volumetric strain of collapsible loess considering microstructure instability is developed. In this method, loess is regarded as the compound of disturbed part and undisturbed part. The volumetric proportion of the both parts, which represents the state of micro-structural damage and varies with the increase of effective load, can be calculated by the combination of an idealized microstructure model, the pore size distribution curve and the equilibrium criterion for microstructure. The method is verified by comparing the calculated results with the data of triaxial compression tests. In addition, some experiments show that compression curves of loess with different water contents are parallel with each other in the sections that represented progressive damage to microstructure. This phenomenon is successfully explained by the equilibrium criterion for microstructure.

The triaxial compression test results of undisturbed ,remolded and reconstituted samples are analyzed . The grain-size distributions and the structure are considered to be two main factors which influence the stress-strain and strength behavior of silty sands. When the grain size distributions are not the same , not only the undisturbed samples with structure but also the reconstituted samples with non-structure are not similar in strength. The strength of remolded samples which have the same graine-size distributions as the undisturbed samples are different from that of the undisturbed samples. The stress-strain relationship and strength behaviors of one of reconstituted silty sands are very similar to those of the undisturbed samples although their grain-size distributions are different. This kind of reconstituted silty sand can substitute for the undisturbed silty sand in the model test.

The hysteresis effect of seepage variation caused by reservoir water level variation is deeply studied; and then a hysteresis seepage model is presented. By use of this model and optimization analysis，hysteresis days and effective water depth upstream are determined. By introducing effective water depth upstream, an instability seepage problem is converted to a stability seepage one. Based on this simplification and combining measured data and seepage analysis, an analytic model for base flow of dam seepage is proposed. The example shows that the model can simulate behavior of base flow.

The experiment system and the theory of combined dynamic and static loads for brittle rock fragmentation are introduced; and the general forms of force excavating by dynamic and static loads are confirmed. The combined experiments on granite and concrete blocks are carried out with horniness alloy cutting tools through changing the values of WOB(Weight on Bit) or impact energy. And the results indicate that the depth and volume are increased with the increasing of WOB and impact energy, and contrary to the special energy consumption of rock fragmentation. The reasonably combined dynamic and static loads for breaking granite and concrete blocks are respectively 63 J, 2 100 N and 35.15 J, 1 200 N.

The dynamic characteristics of pulsed water jets and the relationship between length of oscillating chamber, standoff distance ,abrasive concentration and erosion rate as well as cutting specific energy for the pulsed abrasive water jet were investigated by experiments under submerged and in the air. The cutting and erosion capabilities of the pre-mixed abrasive water jet and the pulsed abrasive water jet on granite and limestone were analyzed comparatively. It is shown that the self-oscillating frequencies decrease with the length of chamber and increase with the pressure and runoff, the erosion rate of the pulsed abrasive water jet are 70 percent larger than those of the pre-mixed abrasive water jet in the submerged conditions, as well as 40 percent in the air.

An ant colony optimization is applied to estimate the hydrogeologic parameters of aquifers for steady state groundwater flow models according to measured water heads and boundary fluxes. The ill-posedness of the inverse problem as characterized by the instability and the nonuniqueness is controlled by making use of computational intelligence. Compared with gradient-type methods, the ant colony optimization is able to converge to global minima for estimating model parameters. A set of numerical experiments are conducted to illustrate the methodology. The results achieved are compared to those previously obtained by a simulation procedure. The research shows that the parameter identification procedure proposed has the characteristics of robustness, global convergence and the ability of fitting measurement noises.

Static heavy load test of over-length drilled pile is carried out by taking prestressed working pile as part of anchor system，the test equipment is set up capable of heavy weight loading. On the basis of in-situ data of test, the bearing behavior and load transmission characteristics are analyzed. There is no obvious failure feature in over-length drilled piles. The vertical load transmission mostly depends on the side friction of pile, and there is an optimal range of depth for side friction. Besides, the bearing capacity of over-length drilled pile will also be influenced by the factors like constructing technologies and soil properties.

The strengthening effects of reinforced concrete liner cover for tunnel lining with crackles are investigated, and the numerical simulations for two computations of Tieshan Tunnel and Dayakou Tunnel are carried out by using a 2D FEM code. The computation results show that the stress intensity factors at the crackle tips can be decreased greatly; and the bearing safety factors of the linings can be raised obviously.

By using homemade shear equipment, the shear tests of rock mass which has natural discontinuities from the Three Gorges reservoir area are carried out under different states; the deformation and intensity curves of different models are drawn. After analyzing the experimental data we conclude that the shear strength of discontinuity is relevant not only to positive stress but also to water content of the discontinuity of the rock mass; that is, the shear strength rise with the rise of the positive stress and decrease with the rise of water content. Finally, we compare the shear strength parameters which with the theoretical data, and find the two groups of data are consistent. The paper also proves the experimental device and method are feasible and valid in engineering application.

Based on analyzing the causes of information, material components and structural characters of the common expansive soil and the red clayed soil in Guangxi, some thermodynamics tests have been done on the red clayed soil and the expansive soil under normal temperature (-4 ℃-60 ℃) to search their thermodynamics characters and their relations between shear strength index and temperature. According to the tests,（σ1-σ3）peak value of the two kinds of soils do not change much under the indoor temperature (28 ℃) and the temperature of 10 ℃, 40 ℃ environment respectively, while under the temperature of 60 ℃ the change is obvious. Under the same conditions the main difference stress peak value of the red clayed soil has a greater change. The shear strength indices c,φ of two soils change with the hot state accordingly. Furthermore, the cohesive stress c of the red clayed soil and the friction angle φ of the common expansive soil are less relatively in the indoor temperature environment. From the tests we can conclude that the tendency of the thermodynamic influence on the red clayed soil and the expansive soil is similar, but the red clayed soil is more sensitive to the thermodynamic change. All these differences are caused by the genetic type and agglutinate character of the common clayed soil. The result of study offers reference for reducing the disasters and taking precautions against the calamities so as to help the construction on the red clayed soil and expansive soil area.

Aiming at improving the analysis precision of reflection waves in nondestructive detection for civil engineering foundations, the characters of Morlet and Marr wavelets and the properties of their transforms are thoroughly investigated and the complementary advantages of these two wavelets in reflection wave analysis are discussed in detail. By combining the advantages of these two wavelets, a novel method for reflection wave analysis is proposed, which utilizes power density spectrum of Morlet wavelet to extract the dynamic characteristics of reflection waves and employs modulus spectrum of Marr wavelet to capture the singular features of reflection waves, in addition involves the key technique of using Shannon entropy of wavelet transform to determine the optimal mother wavelet of Morlet wavelet. Damage patterns may be identified in terms of the dynamic characteristics of reflection waves and damage positions may be located in terms of the singular features of reflection waves. Thus a promising technology is constituted for nondestructive detection of civil engineering foundations. The basic damage patterns of civil engineering foundations are demonstrated in the physical model experiment, and the feasibility and effectiveness of the technology are validated by both numerical and physical experiments.

The rock mass fracture is very developed because of its special rock property in karst area, which results in the developed fracture network of rock mass, the fracture channels are very easy to form the connected network. Under the action of chemical corrosive water, the channel of fissures will be widened, which leads the leakage increase. Based on the developed characteristics of rock mass fissures in karst area, fracture network of rock mass is plotted. The development degree of rock mass fracture is simulated by using the 3-D Monte-Carlo modeling technique. At the same time, the chart of fissure connection is also simulated; and this chart can exhibit the developed direction of dominant fracture in karst area. On basis of the joint network, all kinds of fracture and pore in karst area are divided into four levels by the scale and permeability of fracture and pore; i.e. level-1 real fracture network, level-2 random fracture network, level-3 equivalent continuum and level-4 continuum; the relation of each level fracture is established by the principle of water balance. Then the seepage of rock mass fracture in karst area is analyzed in detail by adopting the seepage models of multi-level fracture networks. The investigation results show that the seepage models of multi-level fracture networks are applied to the seepage analysis of rock mass in karst area, which can reflect correctly the seepage distribution law of fracture mass in karst area; and possesses important reference meanings for solving the prevention seepage and prevention corrosion in karst area.

Finite element method is a familiar method in the calculation of embankment settlement, but it has difficulties in deciding model parameters. Generally, this needs doing triaxial drained test. In order to make this method be practical, some error analyses, which are concerned about the existing simple method for determining tangential elastic modulus of Duncan-Chang model, are done and related modified coefficient is also brought forward. Furthermore, an approximate formula for determining tangential Poisson ratio, suitable for both sandy and cohesive soils, is given according to the K0 status of soils. Example shows that the above methods have definite reference value in common road engineerings which need settlement calculation with FEM but lack of triaxial test materials.

The load transfer function method (LTFM) is a significant means of load transfer mechanism analysis of pile. The paper divides the soil surrounding the pile into two parts, the elastic area and plastic area for the common action of pile-soil. According to the law of linear increase of shear strength with the depth of natural ground, it gives the solution by the basic differential equation of load transfer function. And the practicability of the method is illustrated by an actual example.

There is no perfect calculation method for soft foundation instant settlement at present. And the environment of the seaside soft foundation is very complicated. As the foundation is always affected by the tide, in general, there exist embankments in the two sides. The measurement data from a seaside road foundation treatment project in Xiamen are used to analyze instant settlement, on the condition of considering the influences of embankment. Finally the instant settlement calculation method is established. As the parameters about the method are obtained from the measurement data in Xiamen area, then it can calculate the soft foundation instant settlement very well there; in addition it also can be used for some other places in the similar conditions.

The stability of single cavern roof is studied with cusp catastrophe model of large deformation circular plate with fixed supports. The necessary conditions of instability are deduced. Considering the level stress contributed under the weight of strata and geological construction, the cusp catastrophe of connected well roof is analyzed with cusp catastrophe model of beam model. The sufficient and necessary condition of instability is deduced, which is the theoretical base of the cavern’s stability controlling and national strategic oil storage in the cavern.

In excavation engineering, the depth of retaining wall is generally determined by the analysis of anti-heaving stability. The checking formulas of current codes, arc-slippage method, is suited to general conditions, especially in the condition of flexible retaining wall. Considering the characteristics of top-down construction and other advantage factors, a so-called modified arc-slippage method is proposed for rigid retaining wall. And with the analysis of engineering instance, the depth of diaphragm wall in top-down construction could be optimized.

Generally, the action of wave forces to piles is calculated separately by dissociating piles from the structure of piles, soils and base slabs (PSBS) in harbor, bridge and ocean engineering. Based on the interactive model of PSBS that we put forward before[1], we conduct a calculation and an analysis of piles loads and bending moments of PSBS under wave loads by combing an engineering example. The result shows that the calculated results by the interaction model are very close to the results by the criterion method with no wave force. Thus, the applicability of the interaction model is test and verified. And then, we considering a whole system that composes of wave load and PSBS by adding the wave loads, analyze its mechanical effects of the PSBS under wave loads with the changes of external load, wave load and the coefficient of soils around a pile of a base slab.

Anchor frame beam is a good method for strengthening the expansive soil roadcut slope. However its design theory is still not uniform and there is no any code to be followed. Engineering experiences are important for the design of anchor frame beam. The assumption of Winkler foundation beam and semi-infinite elastic theory are used for calculating the internal forces of anchor frame beams.The internal force distributions of different length beams are analyzed.The results show that it is illogical to design the frame beam just by expansive force. It is suggested that the internal forces of anchor frame beam to be calculated with Winkler foundation beam and semi-infinite elastic theory. At the same time the pertinent proposal for designing frame beam is offered based on an actual project.

The characteristics of Love wave induced by vehicle loads are of tremendous importance to both dynamic response of structure and exploration of the soil profile. Analytical method is applied to construct the displacement distribution equation and the dispersion secular equation of Love wave generated by vehicle loads in two-layered ground. The dispersion characteristics and displacement distribution of Love wave under various loads are discussed. The results prove Love wave induced by vehicle loads is different from the Love wave induced by other loads; the properties of Love wave generated by vehicle loads are not only related to the thickness, mass density and shear wave velocity of the layer soil, but also related to compression wave velocities in soil.

The difference between the two grids for three-dimensional visualization and the element for numerical simulation in geotechnics is obvious due to the variety of data structure. Consequently, it is of much importance to study the integration of three-dimensional visual modeling and mechanical analysis. After dissecting mesh properties of the three-dimensional visualization and the numerical simulation, a method of loose mode which converts three-dimensional grid to FLAC3D element is brought forward. Its application to a submarine tunnel proves that it is reasonable and effective.

Under the counterforce on the rectangular open caisson working well during pipe jacking, the backwall displacement curve was assumed to be parabolic and the relation between the displacement and earth pressure was used to calculate the earth counterforce. Then considering the friction forces on the well sides and well bottom, the permissible jacking force was calculated through the horizontal forces balance of the whole working well. Through an example comparing the new method with Rankine theory, it was shown that the new one can calculate the earth pressure at the un-passive state and considers the effect of the local force on the earth pressure distribution on the backwall.

Due to uncertainty geotechnical parameters, the higher security coefficient is not always stable in the analysis of deep excavation against heave stability. Therefore, this paper puts forward a reliability analysis method for deep excavation against heave stability, and develops corresponding computer programs based on the Rosenblueth method to research the influences of soil property parameters c and φ variation on reliability indices. In addition, the paper analyzes by instances deep excavation against heave stability using the reliability analysis method and security coefficient analysis method. The results show that the reliability analysis method is scientific and reasonable; for complex equations, the Rosenblueth method has an advantage over others in calculating reliability indices.

Based on three-dimensional finite element method, the static analysis, spectrum analysis and nonlinear analysis of the structure of surge chamber of Liujiaxia Hydropower Station have been carried out. Load effects are evaluated in this paper. In accordance with the results of linear FEM analysis, a design scheme of reinforcement is proposed. Then, the strength of the structure and crack width are checked by using the nonlinear FEM. After several times of adjusting steel bars area of the structure, an optimal structure and corresponding reinforcement are obtained.

This study is based on the groundwater system in Pengshan water resources area, aiming at the problem of ground subsidence in study area, applying the theory of soil mechanics and dynamics of groundwater, the aquifer consolidation model under the condition of exploitation in water resources is established. In order to ensure the exactness of this model, making use of seepage spatial field and groundwater movement progress respectively, the author comprehensively evaluates the error cumulating and distribution and the model stability so as to lead to better reliability in the model.

Based on the materials of practical survey on the real excavation displacement of underground engineering，an analytical model of nonlinear artificial neural network has been established. On the basis of above obtained result, the construction control plan can be predicted using fuzzy logical method. It is proved that the application of the ANN-fuzzy logic coupling model to the site construction control of the massif No.211 in Shanghai is successful. All these results have offered a new method for the construction control of underground engineering.

The stability of high slope is a complicated problem in geomechanics, in which field that lots of factors may be involved; so the in-situ monitoring has become an important measure to ensure its safety. Related to a practical project, and based on the analysis of data that have been collected about the deformation of slope and the stress of support units, the stability of high slope during the period of construction and operative process is analyzed; and various influencing factors for the stability of high slope have been brought forward. These conclusions have provided a reference for similar projects.

Based on computerized tomography two-phase ray tracing technique, quality of concrete member has been tested. Professional test equipment is used to attain projection data without damage test member interior configuration.By using selected mathematic model and image reconstruction techniques, the solution for inverse problem is obtained. It also forms 2-dimension and 3-dimension images to show the inner performance characteristics. The full information of the tested section of the concrete members can be supplied; and the detail flaws can be detected effectively and accurately. Computerized tomography technique is structure disease test mainstream; the method’s foreground is wide due to its cheapness, speediness, much data, and various modes.

In designing anti-seepage wall of reservoir’s dam foundation, there always have the inclination of over-security because of lack of testing or just using old analytical method. To solve this problem, this paper based on optimization theory, and by using the 2D finite element method, realized the optimal choice of the thickness and depth of dam foundation’s anti-seepage wall at Yanshan reservoir, in Henan Province. Firstly, the seepage fields of the dam foundations that have anti-seepage wall of different depth and height were modeled. And by comparing the calculating hydraulic gradients and seepage amount with the permissible hydraulic gradients and seepage amount, the optimized anti-seepage has been obtained as follows: the depth is 0.8 m, and the height is 5 m into the fractured area.

According to the general rule of ground deformation due to tunnel construction, the effect of tunnel excavation on existing objects is analyzed. Combined with the underground passage project between south and north square of Changchun Station, which crosses the existing rail lines, platforms, postal passages and several underground pipes, taking the permissible unequal settlement of existing structures in the code as controlling object, the controlling norm is established for surface settlement due to tunnel construction by basic mathematic and mechanical analysis methods. The established norm has assured the safety and smoothness of construction and has been proved by the construction practice.

Engineering geological condition, footing, weak underlying layer examination, allowable bearing capacity of compound subsoil, earthquake hazard evaluation, settlement, tilting, excavation and dewatering works for the 3 tall buildings in Xinhejiayuan Community are introduced. In the projects, the composite subsoil of piles with rammed and enlarged base forms a similar mat foundation under box foundation; and by the effect of jostle dissolves stratum liquefaction the piles don’t drill through so as to shorten piles greatly and lower greatly the soil treatment cost. Not only the blank of geotechnical investigation & design for tall buildings in Renqiu District has been filled up by the projects, but it is also pointed out that piles with rammed and enlarged base are important to tap the potentialities of shallow liquefiable stratum.

The recent development of research on pressure transducer static matching error in rock and soil is described briefly. The approximate analytic theory and uniform quantitative calculating formulae of matching error are deduced; and optimum indenting displacement coefficient is obtained. The relation between two matching conditions is established; and the stress distributions on transducer sensing surface and in soil around transducer are given.