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2006, 25 (02): -216 doi:
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2006-02目录

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CONCEPTS AND METHOD OF SLOPE FLEXIBLE STABILIZATION SYSTEM

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2006, 25 (02): -217 doi:
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There are some obvious errors and incompleteness in the existing(available) dimensioning concept of GTC flexible slope stabilization systems made of high-strength steel wire mesh in combination with anchor bolt. First，the forces on the mesh resulting from partial instabilities are treated as two independent forces that can¢t be mathematically determined because only one equilibrium equation for them can be formulated. One of the two forces has to be artificially assumed. Second，the longitudinal tensile force of the mesh is assumed as only transmitting to the upper nail；that is，the ability of the GTC flexible system transmitting force all around is neglected. The force concentration degree of the mesh at the upper nail is overestimated；and the dimensioning results are too conservative. Third，the existing concept doesn¢t consider the determination of the lowest force against pull-out of nail. In view of this situation，based on the action mode，the Mohr-Coulomb criterion and the limit equilibrium principle，the concepts of the GTC system are corrected and perfected. Furthermore，the safety checking requirements and the methods to determine the bearing resistance of the systems are established；and the methods to determine the anchoring requirement under different conditions are put forward. So the dimensioning concept and method of the flexible slope stabilization system are perfected.

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STUDY ON STABILITY OF HIGH ROCK SLOPE
IN HYDROPOWER ENGINEERING

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2006, 25 (02): -226 doi:
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During the construction of hydropower station，high cutting rock slopes are inevitably encountered，especially in the areas full of huge mountains and gorges. To some extent，the research on the stability of rock mass and the high cutting slopes in the areas of hydropower station is more important than that of the dam itself. According to the research on the stability of intake slopes of Jingpin Hydropower Station，which is located on Yalongjinag River，the study methods of huge mountains and gorges are systematically summarized. First，a field investigation on geological condition and the rational parameters of rock mass is taken. Then，the possible failure style of the slopes is estimated. Because the terrain has great influence on the stability of the slopes in this area，a precise model，which can reflect the topography vividly，is established to analyze the stability of the slopes. During the process of the analysis，many methods are used to verify the results. The following conclusions can be drawn：the general stability of the intake slope of Jingpin Hydropower Station is acceptable，while some measures should be taken to reinforce the slopes in the upper layer of . The research，not only ensures the safety of Jingpin Hydropower Station，but also provides some helpful experience to the stability research on high cutting slopes of similar projects.

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DISCUSSION ON VEGETATION METHODS AND STABILITY OF SLOPES REINFORCED BY SNS ACTIVE PROTECTION SYSTEM

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2006, 25 (02): -235 doi:
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SNS(safety netting system) active protection is an open system to reinforce slopes. Considering its merits—easy to install，high efficiency，low cost and artistic effect on slopes，it has been widely used in many fields of domestic industries，such as hydropower station，civil transportation and mining engineering. Though the feasibility of combining herbage protection with the SNS active system does exist，few practical engineering using this method were put into effect. The study on this issue is also scarce. In this paper，the authors summarize the conventional ways to afforest slopes，discuss the feasibility of combining SNS active system with slope vegetation，and suggest that three vegetation ways can be used to the slopes reinforced by the SNS active system. The authors also advise proper amendment of these vegetation ways. A new method of evaluating the stability of the slope protected by the flexible active protection system is put forward. The reinforcing effect of slope protection with herbage at shallow layer is demonstrated；a simplified geometrical model to simulate the situation of the slope is proposed，from which formulas used to calculate safety factor can be deduced；and a practical engineering slope is used to testify the formulas. The results show that the formulas are applicable. The following conclusions can be drawn as follows：(1) the SNS active protection can successfully reinforce slopes；(2) the SNS-herbage protection overcomes the inconvenience of traditional ways to reinforce slopes，improves the effect of the vegetation，and becomes a developing method with ecological and social benefits. So，the SNS combined with herbage protection is recommended.

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GEOTEXTILE DESIGN OF REINFORCED EARTH WALL WITH INTERMEDIATE PRINCIPAL STRESS IN CONSIDERATION

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2006, 25 (02): -241 doi:
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Generally，the tension and anchorage length of geotextile are calculated based on Mohr-Coulomb strength theory，and the intermediate principal stress is not taken into account. The influence of intermediate principal stress can be considered with twin shear theory，and the parameters of Mohr-Coulomb strength theory ( ， ) are modified with the twin shear strength parameters ( ， ). Based on the twin shear theory，the tension and length of geotextile are modified. The example shows that the tension and anchorage length of geotextile with twin shear theory( ) is close to that with Mohr-Coulomb strength theory when the wall height is small；while upon a further increase in wall height，the tension and anchorage length of geotextile become bigger than those calculated by Mohr- Coulomb strength theory.

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SIMULATING ANALYSIS OF SLOPE STABILITY UNDER
FLEXIBLE PROTECTION IN OPEN-PIT MINE

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2006, 25 (02): -246 doi:
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In light of the problem of slope stability under flexible protection in open-pit mine，a numerical analysis model is established by using the theory of elastoplasticity. According to the elastoplastic model，the influence degree of blasting shock on stability of the high-deep rock slope is imitated by using elastoplastic finite element method；the displacement field and the safety factor of the slope with fault at later stage are computed. The numerical analysis results show that the proposed flexible protection system is valid and applicable to the rock slope engineering in mountainous areas.

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STUDY ON ECOLOGICAL PROTECTION MECHANISM OF RED BED MUDSTONE SLOPE

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2006, 25 (02): -250 doi:
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The ecological technique has been widely applied to the protection of the red bed slope recently；nevertheless the red bed mudstone slope ecological protection theory is not systematically studied. By selecting the typical red bed mudstone slope，the mechanism of the ecological protection of the fast weathering of the red bed mudstone slope surface is studied by the field rainfall tests with the ecological protection and without it and the long-term monitoring tests on the temperature field and the moisture content of the shallow layer of red bed slope. It is concluded that the ecological protecting functions on the fast weathering of the red bed mudstone slope include eliminating the weathering material erosion and changing the temperature field and the moisture content of the shallow layer bed mudstone slope. More importantly，the ecological protection prevents the red bed mudstone slope surface from rain，making no high difference in temperature and the thermal stress in the shallow layer. So，the fast weathering of the surface is eliminated.

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EFFECT OF STRAW FIBER，POLYACRYLAMIDE AND SUPER ABSORBENT POLYMER ECO-ENGINEERING ON ROCK SLOPE PROTECTION

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2006, 25 (02): -257 doi:
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Substrate，which is the most important material in eco-engineering for rock slope protection(EERSP)，is the substance basis for stable growth of vegetation. The function of substrate relies on the effects of functional materials under condition of limited substance. The primary functional materials，including straw fiber，polyacrylamide(PAM) and super absorbent polymer(SAP)，are investigated quantitatively with functional effects. The results show：straw fiber can keep the stability of substrate by improving the shear strength of substrate，delaying the time of cracking，reducing crack width，and decreasing sediment loss from erosion. However，it is disadvantageous to add too much straw fiber. PAM can improve the precipitation infiltration of substrate，delay runoff time，decrease runoff volume on slope，and increase water stable aggregate content，therefore，improve the anti-erosion capacity of substrate. In addition，the porosity of substrate will be enhanced simultaneously to make the structure of substrate loose and maintain favorable infiltration and air penetrability for promoting vegetation growth. Nevertheless，the effect of PAM，which has significant temporal scale influence and decreases with time，is constrained to certain amount. Appropriate SAP can improve water sucking capacity of substrate，enhance available water content，restrain evaporation，delay wilted point time，and raise anti-drought capacity remarkably. But the course of suck-release can not be reused without limit. The vegetation growth is retarded when excessive SAP is applied to substrate. Under experimental condition，the favorable amount of sucking straw fiber，PAM and SAP is about 4 kg/m2，10 g/m2 and 80 g/m2，respectively.

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MECHANISM ANALYSIS AND MONITORING
FORECAST OF LANDSLIDE AT ROAD TUNNEL FACE

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2006, 25 (02): -268 doi:
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Because of engineering geologic condition，hydrogeological condition and artificial factor，it is easy to result in landslide at tunnel face. Taking the Henglutou tunnel face engineering of the Hangzhou—Qiandaohu Expressway in Zhejiang Province as an example，firstly，the mechanism of landslide is analyzed in three aspects such as geological factor，water effect and human factor. Then，the landslide process and feedback monitoring data are dynamically analyzed；and the effect of construction measures is checked up. Finally，the process of landslide is simulated by FEM of Plaxis. Through effective monitoring dynamic feedback，the slope at tunnel face can be controlled；and landslide can be forecasted. The construction risk of tunnel face could be reduced greatly and construction safety of tunnel face could be assured.

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STUDY ON FAST WEATHERING CHARACTERISTICS OF
RED BED MUDSTONE SLOPE

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2006, 25 (02): -275 doi:
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The fast weathering universally takes place in red bed mudstone slope，which is not completely solved till now. By selecting the typical red bed mudstone slope and monitoring its fast weathering in the field，it is shown that the fast weathering of the red bed mudstone slope is from surface to inside and mainly appears within 10 cm in depth below the surface，and that the variation of air temperature and rainfall has important affects on the fast weathering of the red bed mudstone slope. According to the mudstone block weathering experiments，it is also confirmed that the block weathering is very slow in the condition of unchangeable daily air temperature and moisture content. Based on the mudstone block temperature variation experiments and the finite element analysis，it is concluded that the main external factor affecting the red bed slope fast weathering is the rainfall in the high temperature state；and it offers a theoretical foundation for the ecological protection of the red bed mudstone slope.

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A MODEL FOR CALCULATION OF INTERNAL FORCE OF MICROPILE SYSTEM TO REINFORCE BEDDING ROCK SLOPE

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2006, 25 (02): -284 doi:
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According to the arrangement of micropiles，the micropile system used to reinforce bedding rock slope can be classified into three types：independent micropiles system，planar truss micropile system and spatial truss micropile system. On the basis of combining the mircropiles and the rock mass among the micropiles as a whole structure，a new analytical model of micropile system is proposed. The interaction between the micropiles and rock mass can be simulated with this model. The mathematical and mechanical model for the internal force and deformation of the micropile system is established by finite element method.

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DETECTION OF EFFECT OF HIGH-PRESSURE ROTARY SHOTCRETING GROUTING ON RIVER BED COVER

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2006, 25 (02): -289 doi:
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With the development of grouting technique，it is widely used to treat soft soil. But in water conservancy and hydroelectric engineering，it is still very little to treat clay foundation with grouting. Through an engineering case，a series of detection methods，such as rock coring，high pressure water and loading test，and sonic test，ect.，are described in detail. At the end，it is pointed out that the river bed cover treated with grouting can¢t be used as composite foundation.

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STABILITY EVALUATION OF SLOPE PROTECTED BY FLEXIBLE SYSTEM

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2006, 25 (02): -294 doi:
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The flexible protection system has been widely used in slope protection against geological hazards. However，the design of this system is mainly preformed based on the experience of engineers. Few methods can be used to evaluate the slope stability. A new method for evaluating the stability of the slope protected by flexible active protection system is put forward. First，the strengthened force of unit steel wire net can be obtained by analyzing the steel wire material. Secondly，the boundary of the maximal potential fail rock block can be determined by field investigation，and the safety factor of the rock block can be calculated through the formulae deduced from the classical wedge theory. In practical calculation，the designer can define the design safety factor beforehand，and the volume of the maximal rock block protected by the flexible system can be obtained based on field investigation. The comparison between the maximal volume and the field rock blocks is made. If the maximal volume is larger than all the field rock blocks，the stability of the slope is acceptable. Otherwise，the slope must be reinforced.

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RESEARCH ON GREENING PROTECTION MECHANISM FOR ENGINEERING SLOPE

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2006, 25 (02): -299 doi:
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In the construction of civil engineering，the local environment will be destroyed. Not only is the greening project advantageous to resume the natural environment destroyed，but also the roots of vegetation will strengthen the surface of slope. In respect of vegetation growing，the slope is reclassified；the roots protection mechanism is studied. Then the stability of the protecting layer is studied by test and numerical simulation. The results show that the effect is different for different structures of rock mass. In order to guarantee the stability of the protecting layer of slope，according to the classification，height and slope rate，the proper methods with other measures should be applied.

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STABILITY ANALYSIS OF BLOCK IN SURROUNDING ROCK MASS OF LARGE UNDERGROUND EXCAVATION

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2006, 25 (02): -306 doi:
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The key block has received a lot of attention in underground engineering because it loses stability first after excavation. The block theory originally proposed by Shi doesn¢t deeply discuss the geometric characteristics and explain how to determine the precise locations of the key block. Therefore，the Unwedge program based on key block theory can not predict complicated polyhedral block and determine its precise location. In this paper，the stability of key block of a large underground excavation is analyzed in detail. First，the Unwedge program (Ver.2.35) is used to identify possible key blocks and some limitations are discussed. Then，many kinds of geometric models of polyhedral key block are set up and a new computer program is developed to search key blocks and determine their precise locations considering the action of gravity and dynamic loadings. Finally，the results of the two methods are compared and the differences between them are analyzed.

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RESEARCH ON APPLICATION OF FLEXIBLE PROTECTION TECHNIQUE TO JINHUA—WENZHOU RAILWAY ROCK FALL TREATMENT

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2006, 25 (02): -312 doi:
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The flexible protection technique has the properties of easily spreading，high ability against impact，fewer vision interference，original vegetation and landform maintains，and good environmental effect. It is proved to be a valid method by engineering practice. This paper introduces the application of flexible protection against falling rocks in Jinhua—Wenzhou Railway based on the experiences of tackling the falling rocks. The paper also discusses the engineering features of the flexible protection，its mechanism and the design parameters of the type choice，the length of rock bolt，and construction arrangement. It can provide reference to the similar protection design and construction.

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DESIGN OF SUPPORT OF FRAME BEAM AND PRESTRESSED ANCHOR

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2006, 25 (02): -318 doi:
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In view of the support effect of prestressed anchor and frame beam，the support of frame beam and prestressed anchor is widely applied to the reinforcement of slope. According to the characteristics of anchor and frame beam，the reinforcing mechanism of the support is discussed. Through analysis of the load system on frame beams，the calculation method of internal force and main design parameters are introduced. According to the condition of prestressed anchor，two phases such as tension phase and working phase are divided. With respect to the working phase，the soil pressure on frame beam is determined by using the slope thrust to back-calculate the tension of prestressed anchor and calculate the internal force of beams.

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TYPICAL CASES OF SLOPE FLEXIBLE PROTECTION SYSTEM

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2006, 25 (02): -323 doi:
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Some typical cases of flexible protection systems used in the slope protection projects in China are presented including kinds of the construction patterns and flexible net types of the flexible protection systems that have been used in China，such as active stabilization，confining protection，rockfall barrier，wire rope net，high-strength steel wire mesh and ring net，etc.，in order to demonstrate how to adopt the flexible protection systems and the advantages of the system in technology and economy. These cases indicate that the flexible protection system has obvious advantages when the installation field is restrained，the time limit for a project is urgent，the slope is steep and the rocks are scattered. It should be advertent that different landform，geological conditions，hazard field conditions will influence the choice of the system.

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EXPERIMENTAL ANALYSIS OF EMBANKMENT WITH PREFAB FRAMEWORK SLOPE PROTECTION OF QINGHAI—TIBET RAILWAY

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2006, 25 (02): -329 doi:
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The severe environmental temperature variation and special geological condition in Qinghai—Tibet pleateau would induce frost heave and thawing settlement in embankment slope，leading to collapse of slope face due to soil strength decreasing. To ensure man-made slope stability in certain period in permafrost region in pleateu，in-situ experiments of embankment with prefab assemble framework slope protection were designed and carried out in Beiluhe，an area with thick ice in ground. The prefab assemble framework divides large area of embankment slope face into many rhombic pane structures，which decreases the scope and thickness of slope soil collapse. The firm connection of prefab framework with slope face strengthens slope integrity. In the meantime，the soil shear resistance and soil anti-scour ability of embankment slope all increases much. In addition，the two connected assemble frameworks，as one side of rhombic pane，being perpendicular to slope face，allowes little displacement which can release frost heaving force of soil in rhombic pane. The anchor-hold and framework connection realizes the plane protection style with lines joining up with points and planes joining up with lines. The observed data show that embankment with framework froze heave in winter and thawes with settlement in summer. The deformation of thaw settlement and frost heaving tends to be steady year after year. Thus，framework slope protection has good effect for maintaining slope face stability.

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PRACTICE AND UNDERSTANDING OF GROUTING TECHNIQUE IN TREATMENT OF HIGHWAY SUBGRADE SETTLEMENT

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2006, 25 (02): -334 doi:
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The settlement of high subgrade is common fault in highway engineering，it not only directly affects the quality and normal operation of highway，but also brings trouble to everyday maintenance. There are some treatments to deal with this problem. The method of the pressure grouting design，construction technique and quality control and test is introduced taking the treatment of high subgrade settlements in Guangyuan section of National Highway 108 for example. Furthermore，the relation between the economical performance and the grout ability of grouting liquid，the concretion rate and the road uplift，site contamination during grouting process are discussed. Finally，the reason for the settlement of the high subgrade in Guangyuan section of National Highway 108 is analyzed；and some advices for construction of the pressure grouting are presented.

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EXPERIMENTAL RESEARCH AND ROCK SLIDING MONITORING OF OPTICAL FIBER SENSING

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2006, 25 (02): -340 doi:
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Optical fiber sensing can be applied to monitoring sliding damage of terrain interface，for which the general monitoring means can¢t do. Based on microbending loss mechanism of optical fiber and optical time- domain reflectormetry (OTDR) technique，the monitoring system of optical fiber sliding sensing and data collection system are constructed. Triaxial shear test of soil is firstly used to construct monitoring system and data collection. The difficulty of optical-mechanical data collection for instantaneous brittle fracture of the solid material is solved. The relation data and curve of sliding distance versus loss are obtained. The embedding mode of optical fiber applied to high rock slope for sliding monitoring is presented. It shows that the optical fiber sensing system is high sensitive，light loss is 30 to 50 dB and the dynamic range of optical fiber sliding monitoring reaches 3.0 to 3.5 mm.

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STABILITY EVALUATION AND FOUNDATION TREATMENT OF HIGH SLOPE COMPOUND ACCUMULATION BODY

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2006, 25 (02): -345 doi:
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The leading water channel is accompanied by some“compound accumulation body”when it passes high slope. It is a combination of bed rock，ancient collapsing body，ancient sliding body and the Quaternary Period precipitation body. By observation，it is found that is the same as the bed rock. Some accumulation bodies may be regarded as cleavage，and are broken and deliquesce heavily. For a high slope of a canyon，its appearance looks like accumulation body，but some part is the same as the bed rock. Part of the lithology is the same as bed rock，while some is changed to crushed stones，crushed stones and soil. It is“compound accumulation body”. After analyzing the reason for formation of it，the treatment methods are proposed.

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RESEARCH ON RELATION BETWEEN DAMAGE EVOLUTION AND STRAIN OF STRATIFIED ROCK

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2006, 25 (02): -350 doi:
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The microstructure of rock is researched by means of scanning electron microscope(SEM)，and a damage model of rock microstructure is proposed. The damage evolvement and breakage process of stratified rock are studied；and the constitutive equations and damage equations are established. The damage variable and damage enlarging variable are used to set up the equations for the whole evolvement of damage and to describe the initial approximate linearity and later accelerating process in rock mass. The damage evolvement and breakage process of rock mass are divided into three phases. The damage evolvement，breakage characteristics and stability of stratified rock are analyzed；and the regularity of damage evolution of rock is explained. The research shows that the appearance and breakage of stratified rock are related not only to load and its rate，but also to the regularity of damage evolution of each rock bedding，the angle of load with stratified rock，and the microstructure characteristics of rock. Therefore，the influence on the in-situ stratified rock is remarkable.

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EXPERIMENT AND ANALYSIS OF SUCTION OF UNSATURATED SOIL IN SLOPE

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2006, 25 (02): -355 doi:
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Rainfall is known as the main factor which affects the stability of slope. With the development of unsaturated soil mechanics，a new way is coming to solve how suction and temporary water pressure affect the stability of slope. During the period of rainfall，water in the slope will change，at the same time the suction and the temporary water pressure will also change with time and rainfall. In order to know the characteristics of the change，the experiments to observe the change of suction and temporary water pressure are conducted. An observation well is built on the Xietan slope of the Three Gorges of the Yangtze River in May 2002. The well has a depth of twenty meters and a diameter of two meters. It is the largest well of observation on suction in the world. The well is put into action；and the data of the suction，temporary water pressure and rainfall is observed in October 2002. The work of observation is finished by the end of 2004. At last，by analyzing a large number of data and records，the character and change feature of the suction and temporary water pressure are found. The conclusions that the distribution of suction is decided by the materials and structure of slope are proved. The change of suction is related to the factors such as rainfall，time，depth，season and so on. The suction doesn¢t change promptly after the rain；there is time difference between the suction change and rainfall. It is obvious that these conclusions will guide to make further studies on how rainfall affect slope stability.

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STUDY OF THEORY AND METHOD FOR NUMERICAL SOLUTION OF GENERAL LIMIT EQUILIBRIUM METHOD

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2006, 25 (02): -363 doi:
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In the conventional general limit equilibrium method，the inter-slice forces assumption of Morgenstern-Price is employed and the safety factor is calculated through the safety factor graphs of the moment equilibrium and the forces equilibrium. A new solution method is presented，in which the assumption about the inter-slice forces is discarded；and the calculation method of the safety factor in the conventional general limit equilibrium is not used either. Instead，the inter-slice forces is united with the definition of the safety factor. A mathematical model of slope stability analysis and an effective numerical simulation method are proposed. The feasibility of the new theory and method for numerical solution of general limit equilibrium method is finally verified with several practical examples.

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A NEW ANALYTICAL SOLUTION OF CURVING FAILURE SURFACE IN BACKFILLED CLAY BEHIND RIGID RETAINING WALL

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2006, 25 (02): -371 doi:
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In practice of soil slope engineering，most research work on earth pressures employs the same assumption that the failure surface in the backfilled clay is a plane. In fact，a number of laboratory and field tests have proved that the failure surface is actually a curving surface. Based on the vertical differential element method and the variational principle with movable boundary，a differential equation for the failure surface is deduced. Two cases of the equation are discussed as follows：(1) no lateral shear force exists at the interface between two elements，and the back of the retaining wall is frictionless. The failure surface is a plane，identical to Coulomb¢s theory. (2) lateral shear force exists，and the back of the wall is rough. The failure surface is a curving surface. The results show that the proposed approach can predict the failure pattern of the backfilled clay，which is in good agreement with those of the laboratory and field tests to certain degree. Finally，the effects of the properties of backfilled clay and the smoothness of the retaining wall on the angle of rupture are discussed.

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STUDY ON GENERATION AND EVOLUTION OF MAOPING LANDSLIDE ON QINGJIANG RIVER

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2006, 25 (02): -377 doi:
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The Maoping landslide is located on the right bank of the Qingjiang River，Geheyan Reservoir Area in Hubei Province of China. It is an ancient landslide with a volume of 2.35×107 m3. After Geheyan Reservoir impoundment in April 1993，the Maoping landslide becomes the most dangerous landslide in Geheyan Reservoir with a maximum displacement of 2 100 mm until now. According to the development history and geological environment of the Qingjiang River valley and bank，the upper time limit of the Maoping landslide occurrence is estimated at Epipleistocene by valley evolution analysis. The component and structure characters of sliding surface and sliding mass are studied. By using the engineering geomechanics analysis method，the origin and cause of sliding surface and sliding mass are studied. The sliding surface comes from primary stratum of D3h and generates after weathering. The sliding mass comes from rock falling mass of slope back side. The process of the Maoping landslide formation and evolution is discussed. On the basis of above analysis，the generation and evolution of the Maoping land slide are deduced. The activity of the Maoping landslide has intimate relation with the rock falling of slope back side through landslide evolution process analysis. Moreover，the displacement monitoring shows that the intensive rainfall has important contribution to landslide. Therefore，attention to intensive rainfall and rock fall monitoring is advised.

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ANALYSIS OF SHEAR FORCE BETWEEN SURFACE SOIL AND VERTICAL SHAFT IN MINE

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2006, 25 (02): -385 doi:
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The purpose of this paper is to find the distribution laws of the shear force between vertical shaft and surface soil，and to lay a foundation for mechanical model of shaft in soil. The formation and characters of elastic shear force and plastic shear force are analyzed. The problems existed in the past research are discussed. The Mohr-Coulomb¢s strength theory，the stress state theory as well as the shear displacement method in soil mechanics are applied to research the variation laws of two kinds of shear forces with soil depth. The calculation formulas of two kinds of shear forces are obtained. The result will play an important part in the analysis of the stress distribution laws and the stress variation laws in dangerous point in shaft and in the research of the forecast theory of shaft rupture. The research result has reference to the study of the shear force between pile stake and soil.

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STUDY ON TREATMENT OF HIGH-CUT CARBONACEOUS SHALE SLOPE IN EXPRESSWAY

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2006, 25 (02): -392 doi:
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The Meizhou to Meinan section of the Shantou—Meizhou Expressway lies in the east of Guangdong Province，which connects the northeast and southeast mountainous areas of Guangdong littoral region. Its construction is important in completing the expressway network，providing access to northeast mountainous areas，improving the investment environment，and further accelerating economy development. The route is 12.288 km long with designed speed 80 km/h，and four lanes in both directions and with whole cross section. The subgrade width is 24.5 m. In the K1+300–K1+600 section，the cut depth of right side is more than 30 m and the left side is more than 50 m. This article is combined with the slope prevention example in this section，the methods of dynamic design and construction for with high-cut slope with carbonaceous shale in unfavorable season are presented. Because construction time is limited and rain is often heavy in summer，this section is constructed during period of light rain. Based on slope datum，preliminary slope treatment is designed. Then the nature of rock conditions，the rock flaw water increment and the directions of rock layer etc. are continually observed. As a result，the design can be adjusted in time according to new conditions. The principle of from up to down，excavation and prevention for each stage are put forward. In addition，draining of rock flaw water，spraying concrete and strengthening action of anchor-stick grid beam are adopted. In the late of 2003，this expressway was completed and slope prevention measures were adopted.

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APPLICATION OF STEEL-TUBE BORED GROUTING ANTI-SLIDING RETAINING WALL TO TREATMENT OF LANDSLIDE K108 IN BEIJING—ZHUHAI EXPRESSWAY

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2006, 25 (02): -399 doi:
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Steel-tube bored grouting anti-sliding retaining wall is a technique of combining grouting with micropiles，which is treated as a retaining wall in mechanical analysis. The most significant feature is that steel-tube bored grouting anti-sliding retaining wall changes a part of sliding mass to anti-sliding mass. Taking the landslide K108 of Guangdong segment of Beijing—Zhuhai Expressway for example，the strata lithology，geologic structure and hydrogeologic feature of the landslide are introduced；and the five slip surfaces are found by displacement monitoring. The landslide is reinforced by steel-tube bored grouting anti-sliding retaining wall and discharging groundwater from sliding mass；the properties of rocks and soils in the landslide are checked by means of PS wave test and pressuremeter test. The landslide K108 is proved to be stable by means of analysis of monitoring displacement and stability computation. The results show that the steel-tube bored grouting anti-sliding retaining wall is an effective method for treating landslide.

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FUZZY-RANDOM RELIABILITY ANALYSIS OF BLOCKY ROCK MASS IN SLOPES

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2006, 25 (02): -407 doi:
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Slope stability assessment is a difficult geotechnical problem because of the uncertainty involved. These uncertainties possess both randomness and fuzziness. Historically，all uncertainties were assumed to follow the characteristics of random ones. However，some uncertainties，especially those based on incomplete information，cannot be handled satisfactorily by the classical random analysis；and in this case，using a fuzzy number to reflect the uncertainty is reasonable. In this paper，a fuzzy point estimate method is presented for the reliability analysis of rock block incorporating block theory and fuzzy sets. As a typical example，it is applied to the stability analysis of a key block in high slope of the permanent shiplock of the Three Gorges Project. Furthermore，it is compared with the fuzzy possibility approach showing that the results by the two methods are essentially consistent. However，the fuzzy possibility method only considers the ambiguity of limit state function and doesn¢t take into account the fuzziness of mechanical parameters. The fuzzy point estimate method provides an effective approach to solve this problem and it can reflect the real situation better because it uses fuzzy-based disposal to every mechanical parameters.

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STUDY ON STABILITY OF REPLACE WITH OUT-SOIL IN ECOLOGICAL SLOPE

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2006, 25 (02): -414 doi:
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[PDF 488 KB] (1178)

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A study is undertaken on mechanical stability of man-made mixture sprayed on slope surface，i.e.，replace with out-soil，in ecological slope engineering. It is found that the failure mode of replace with out-soil is a translated sliding surface parallel to original slope surface from indoor simulation tests. Based on this failure model，stability analysis of replace with out-soil is carried out；and then a general equation for stability thickness of replace with out-soil under earthquake and seepage is given. Stability design charts for replace with out-soil are obtained after discussion on parameters of the equation. Indoor simulation tests testify that the charts are effective. Using the charts，the stability thickness of replace with out-soil can be designed using given design safety factor，vice versa，safety factor of replace with out-soil in constructed ecological slope can be calculated.

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METHOD OF APPLYING ENERGY CONSERVATIVE PRINCIPLE TO STEEL FIBER REINFORCED SHOT-CONCRETE LINING DESIGN

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2006, 25 (02): -423 doi:
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[PDF 537 KB] (1051)

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Different from normal concrete，steel fiber reinforced concrete(SFRC) shows great capacity of dissipating energy in its cracking stage because of the pull out effect of steel fibers. It is of great importance for the design of SFRC structures to study intensively on this energy dissipating property of the material. So the failure of structures with SFRC components will be accompanied by energy exchanges between external environment and SFRC components. However，the total energy of the system should remain constant. To obtain the basic data of steel fiber reinforced shot-concrete(SFRSC) energy properties，a great number of experiments on SFRC specimens are carried out. An analysis based on statistical theory is done to get the energy criterion for SFRSC associated with credibility levels. The data provided by these tests act the fundamental database for further study. With rational supposition，the energy dissipating mechanism in SFRSC cracks is studied intensively. And the relation between the amount of energy dissipated in cracking and the form of cracks is proposed so that the energy data obtained in the standard tests could be used in structure design of linings. Finally，the energy dissipation capacity of the shot-concrete lining is calculated and compared with the tunneling-induced energy release of the surrounding rock obtained through finite element analysis.

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李秀地博士论文摘要

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2006, 25 (02): -432 doi:
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[PDF 99 KB] (806)

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李秀地博士论文摘要