Surface lining system is one of the water-proof methods for dam and reservoirs. Recently, some new Geomembranes (GMs) with various performances have been introduced into this system. However, the methods of performance tests, design and construction for the commercial GMs have not been established yet as well as those of the newly developed GMs. Then, the following technical subjects are discussed in this paper:
The physical properties of GMs which depend on the temperature and the tractive speed.
The influence of weather condition on dynamic stabilities and watertightness at bonding parts of GMs.
The evaluation method of the water-proof pressure of GMs.
The durability of GMs based on the results of the outdoors exposure deterioration tests.

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Various Geogrids are widely utilized and contribute the improvement of stability of embankment. Material properties and pullout characteristics are investigated respectively. However the properties of those geogrids are rarely compared each other and little is known about the effects of different material properties on earth reinforcement. It has been recognized that pullout resistance is important when we examine a stability of reinforced embankment. So pull-out tests were conducted to investigate the effects of difference of material properties of geogrids on pullout characteristics. Special attention was directed to look at the effects of the shape, yield resistance and stiffness of geogrids in this research.

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Fiber-reinforced earth construction methods in which geosynthetic fibers are mixed with soil particles and distributed uniformly within the soil matrix are able to strengthen the engineering properties of earth slope, embankment and foundation ground without any chemical action. Therefore it is one of useful methods to improve the unstable or poor waste geomaterials in order to preserve natural resources and conserve the national environment. However the influence of the geometrical conditions such as length, diameter and shapes and the surface textures of fibers are not yet fully confirmed and hence it is usually constructed based on the empirical design method.
In this study the reinforcement effects of length and surface frictional properties of nylon fibers mixed with pit sands are investigated using a large direct shear box testing and an unconfined compression testing and the experimental results are discussed.

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This paper looks into the tensile force distribution that will produced on geotexitile when the pull-out force acts on geotextile under ground.
An unified view about the tensile force distribution has yet to be reached.
Therefore, we have analyzed by two-mechanical models and we obtained two equations.
This time, we carried out pull-out test in this case to estimate how the equations can use.
As a result, if we can know a frictional coefficient between the geotxtil and soil, it was possible to predict the trend of the strain distribution of geotextile under ground by estimating the tensile force distributions by analyzing.
It can be expected that these analytical methods are useful for designing by the deformation Method.

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In the high embankment construction using high water content clay that is the large scale, belt drains were adopted as drainage in embankment and a good result was obtained by effect of promoted consolidation of belt drains. From the observation result, horizontal displacement became to be small remarkably compared with vertical displacement, during execution and after execution. As a cause, it was thought that reinforcement effect was worked to restrict transformation of embankment. Therefore, plate type strain gauge was installed to belt drains laid in embankment and stress to work to belt drains was measuredand reinforcement effect was confirmed. In the other, observation carried out a displacementof surface of embankment by expansion measure and a transformation of embankment inside by settlement plate and inclinometer.
This paper reports the result of examination into drainage effect and reinforcement effect of belt drains arranged stagger in embankment from the observation result.

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The fill of Noto Airport is constructed rapidly to a height of 55 meters, and its embankment material is high water content clay. Geotextile horizontal drain is installed in the fill to accelerate consolidation. To establish a reasonable method to analyze a behavior of the fill installed the horizontal drain, an applicability of the elasto-visco-plastic FEM is examined in this paper. The result of the simulation is agreed with observed deformation and stress behavior, but horizontal deformation measured is smaller than estimated by FEM. It probably shows that a reinforced effect by friction between the soil and the geotexitile, not modeled in FEM, is produced in fact. Some trial FEM calculations in varies case of the field conditions such as varies embankment speed are done, and a possibility of applying FEM which has the advantage of adapt to complicated conditions to the design for drain placing is shown.

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Spacing of GHD is designed on the basis of slope stability and discharge capacity. This paper concerns especially with the discharge capacity under a generally laid horizontal GHD and a staggered laid one. In the former installation, Giroud's equations is modified to positively include the correlation of degree of consolidation and to compare to Miyata's equation. Under the later installation, the assumption leaded to Barron's equation is analyzed by FEM. After then, the set of equations is proposed to obtain a required discharge.

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Purpose of this study is to propose a unified treatment of the smear effect on a delay of consolidation subjected to a clay layer improved by sand drain (SD) or pre-fabricated band shaped drain (PBD). Therefore, the finite differential method was applied to analysis this problem. As the results, it was found that the trend of delay of consolidation was taken account by the reduction ratio of hydraulic conductivity of clay. This ratio is constituted of the parameter revealing the spacing, thickness of the smear zone, radius of drain, and reduction ratio of hydraulic conductivity. In this paper, the relationship between spacing of drain, delay of consolidation, and smear effect depending on the methodologies of vertical drains is arranged on the same figure and is shown to scatter in the narrow zone.

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Social demand for developing new composite liner system is recently expanding larger to protect human health from landfill environmental problems caused by any leachate of harmful matters from waste deposits.
A colloid-pressurized system was proposed as the central component of composite barrier liners to make waste landfill of high quality in sound waterproof and prompt recovery system. We have developed a self-recovery system, which consists of geomembrane, geocomposite and colloidal liquid. The recovery test was carried out in the laboratory to investigate a governing factor required for a clay liner. The effect of saturated soil by salt water and new product of geotextile on quality of a waste landfill was also checked. Further we confirmed the automatically recovery system through a life-size test.

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One of the important and fundamental functions of geotextiles placed in an embankment or a soil foundation is a transmissivity in its plane and a permittivity in perpendicular to its plane. The geotextile sheet can collect, infiltrate and drain water in the soil mass, for example, problematic cohesive soil embankment of high moisture content. Especially in order to promote drainage of seepage water and to accelerate a consolidation for increasing the strength of the earth materials, geotextiles sheets are embedded in a horizontal direction in the embankment or geotechnical structures.
In this study for the purpose of investigating fundamental hydraulic characteristics of geotextiles, laboratory model tests were conducted using geotextiles having different thickness. This effects of thickness of geotextile, overburden pressure, kinds of soil (volcanic cohesive soil of high natural moisture and pit sand), and head conditions on both transmissivity and permittivity are examined and discussed.

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This paper reports the long-term discharge capacities of 5 types prefabricated vertical drains (PVDs) under clay confinement. The results indicate that under clay confinement, the discharge capacities significantly reduced with elapsed time. The possible reasons for the reduction are creep deformation of the filter of PVD, and clogging of drainage channels. Creep test results indicate that for the conditions considered, the creep deformation is limited, which implies that clogging is a main influencing factor. Test data showed that factors in favor of reducing clogging effect all resulted in an increase on long-term discharge capacity. Based on the test results, an empirical equation is proposed for estimating the long-term in-clay discharge capacity. It is recommended that in term of long-term discharge capacity, a PVD with a larger drainage area per channel and larger shape-factor of drainage channel may be selected. The shape factor is defined as the drainage area per channel divided by its periphery length.

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Puncture resistance of geomembrane is very important property when it is used to a component of liner in waste landfill. An amount of puncture resistance may depend on not only its tensile strength but also a pre-strain and underlying ground strength. In the test, three types of geomembranes such as HDPE, FPA, EPDM and geotextiles called continuous non-woven and stapled non-woven were used as a test specimen.
The authors, first, conducted the puncture resistance test of geomembrane on the modeled ground which was compacted in different strength. Then they conducted the puncture resistance test of geomembrane overlying the geotextile on the modeled ground. As the result, it is found that puncture resistance increased proportionally to ground strength and the ground having more than 700kN/m² of q_c is desirable for the base. Last they lengthened the test specimen by 0% to 20% in length previously to put pre-strained condition and then conducted puncture tests. These tests showed that the HDPE with 20% pre-strain decreased 16% of maximum puncture resistance.

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The damage of geomembrane in landfills caused by a physical factor, a biological factor and a chemical facter. Authors took an experiment when geomembrane was damaged, and considered the influence on the creep transformation and the expansion distribution the geomembrane on the void of a basic ground.

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Geo-composite having a drainage function is often used for stabilizing cohesive soil embankment. In conventional design, only an effect of accelerating consolidation is evaluated. However, it is considered that geo-composite can reinforce cohesive soil when effective confining pressure applied to the soil surrounding geo-composite is large enough and geo-composite has high tensile strength and stiffness to restrain soil deformation.
In this study, pull-out tests using a geo-composite were carried out in order to understand the behavior of geo-composite in a cohesive soil. In a series of tests, two types of cohesive soil having different dilatancy were used. The results from the laboratory test showed that pull-out resistance of geo-composite in the cohesive soil exhibiting positive dilatancy is larger than one in the cohesive soil exhibiting negative dilatancy.

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Two diagrams are proposed to ensure the advantages of geocomposite on improvement of stability, stiffness and permeability of cohesive soils. The one is to plot the increase ratio in bearing capacity against the one in ground reaction coefficient, which was obtained from the results of model footing tests in the laboratory, and the other is to correlate the change in permeability with the one in transmissibity in geocomposite before and after model footing tests. It is emphasized from two diagrams that placement of thin sand layers above and under geocomposite enables to maintain permeability and transmissibity of geocomposite as well as gives rise to marked improvement of stability of cohesive soil embankment.

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Most of geosynthetic are usually employed as a thin sheet-like membrane and reinforce an embankment structure or a poor ground. A geocell mattress, which is one of the reinforced earth construction methods, is assembled in a three dimensional slab structure such as a honeycomb and filled with soil materials. This can improve the mechanical properties of soil structure. The geocell can confine the deformation of soil particles in each cell and a result the geocell slab has a high bending rigidity and shows high stress distribution effects and a restriction of flow deformation of foundation soils.
In this study laboratory model tests are carried out using a two layer system composing a geocell slab placed on a EPS resilient subbase layer. An elastic analysis of the layer under a circular load are made. Experimental and theoretical results are compared and discussed.

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The conventional methods to increase the bearing capacity of ground are physical or chemical soil improvement methods, pile foundation and so forth. At present no efficient and economical reinforcing methods for a weak foundation underneath the facing of reinforced earth retaining walls are proposed for practical use except a mattress foundation using geosynthetic cells.
In this study a newly developed simple and inexpensive foundation reinforcing method using geosynthetic tubes with a bending rigidity is employed. Improving effects on the bearing capacity of subsoil and on the settlement of the foundation soil were examined. A series of laboratory experimental model tests, employing a concentrated loading, were carried out to investigate the strength and deformation characteristics of cylindrical shaped geosynthetic sandbags filled with a compacted pit sand that are parallel-placed on the EPS sub-base layer. The test results are presented and discussed.

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Large-scale model tests were performed to examine the earth pressure on walls retaining geogrid reinforced sand with EPS blocks installed immediately behind the wall. Five tests were conducted with different configurations of EPS blocks and geogrid placement in Toyoura sand of Dr=75%. It is found that EPS blocks installed immediately behind the wall reduces the earth pressure at rest, and also that the use of EPS blocks installed immediately behind the wall combined with geogrid reinforcement connected rigidly to EPS blocks reduces the active earth pressure.

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To gain a better insight into the failure mechanism of reinforced sand, a FEM simulation of plane strain compression tests of dense Toyoura sand reinforced with planar reinforcement having a wide range of stiffness was performed. A new elastoplastic constitutive model for sand, having a stress path-independent work-hardening parameter based on modified plastic strain energy, is applied. The constitutive model of sand is capable of simulating the effects on the deformation characteristics of stress history, stress path and pressure level, taking into account inherent anisotropy in the elastic and plastic properties and work-softening associated with strain localization into a shear band. The FEM code incorporating the above-mentioned new constitutive model is validated by a direct comparison between results from the physical experiments and the numerical simulation for sand specimens reinforced by using relatively flexible and rigid reinforcement as well as an unreinforced sand specimen. The comparison was made in terms of global stress-strain relationships and local strain fields showing the generation and development of shear band. It was found that the FEM code incorporating the proposed model work-hardening model simulates the experimental results much better than one with the previous shear strain-hardening model.

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The granular fill overlying the soft soil is reinforced with one planar layer of geosynthetics which is subjected to axi-symmetric loading. Pasternak's model has been modified to incorporate the ‘tensile membrane’ action of reinforcing layer. Tensile forces within the reinforcement induces confining stress along the interfaces which is being quantified in terms of increase in shear modulus of the granular fill. In this paper variable shear moduli of the granular fill have been obtained based on axi-symmetric loading situation. Nonlinear hyperbolic responses of the granular and soft soil are introduced into the formulation. Parametric study reported in this paper signifies that confinement effect of single reinforcement layer ensures improved response of the foundation. A practical example explains how a single layer of reinforcement improves the shear modulus (G) of the soil compared to the unreinforced granular fill resting on soft soil.

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For construct of railway embankment on poor ground, we used deep mixing method together with geogrid to decrease settlement of ground. Then, we need to understand the behavior of the embankment constructed by this method using deep mixing method and geogrid, caused by static load and dynamic load. So, we did dynamic loading test using two full-scale embankments on site. We will propose a rational method of design for embankment using deep mixing method together with geogrid, by analyzing these two tests. This paper introduces the result of one of these tests.

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Tohoku shinkansen is now being constructed on a very soft ground in the Hachinohe area. In this site, large settlement is predicted to occur on embankments under construction. We applied the geosynthetic sheet and soil cement column method to this site to decrease settlement of the ground. We tried two approaches to use this method; One is a dynamic loading test on the site, and the other is a numerical analysis of this site test.
This paper shows the numerical analysis of the dynamic loading test. We describe the normal stress and displacement of the ground, and tensions of geosynthetic sheets after dynamic loading.

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Generally, as for the design tensile strength of geogrid used as reinforcement material, tensile strength is decided considering creep characteristic. It is also known that the tensile characteristic of geogrid made of polymer material depends on the elongation rate showing large tensile strength under high elongation rate. On the other hand, some methods of evaluating the design tensile strength for a dynamic design are proposed by some organizations. However, those methods aren't yet standardized. Realistically in such reason, the design tensile strength for the static design is also used for the dynamic design. When thinking of the design strength of geogrid in case of dynamic loading, tensile characteristics after creep phenomenon occurs by static load are a problem. Its characteristics depend on static load to make creep phenomenon occur, continuing time, elongation rate which acts on geogrid in case of the earthquake and so on. In this research, the tensile characteristics of geogrid after a creep phenomenon by the static load are tested. The techniques of the data gathering and evaluation, which is the basis about the setting of dynamic design tensile strength, are considered.

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In the construction of Shinkansen railway, the slab track type embankments is applied in order to reduce the maintenance works, as a substitute for existing type of ballasted track. However, the allowable deformation of the slab track type embankments is restricted severely at usual and earthquake states. Therefore, a reasonable and economic design of geogrid reinforced embankment is an important subjects in the seismic design for large earthquakes.
In this report, the required length and arrangements of geogrid reinforcement are examined based on allowable deformation requirement of slab track embankment. Other design parameters, such as: the height and slope of embankment, filled materials, compaction performance and subground conditions are also examined.

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An evaluation method in which the reinforcing effect on geogrid-reinforced soil can be divided into tensile effect and confining effect is proposed. The confining effect is one component of the reinforcing effects and is dependent on the tensile force of geogrid. The validity of the method was verified by the results of a series of new laboratory tests. Based on the proposed evaluation method of the reinforcing effect, failure criterion on the geogrid-reinforced soil is defined and Mohr's stress circle at failure is formulated. The new design method in which the partial safety factor is introduced into Mohr's stress circle on the reinforced soil is proposed. The partial safety factor is defined as a ratio of the radius of Mohr's stress circle on reinforced soil in design condition and the distance between the center of the stress circle and failure criterion on reinforced soil. Finally, as a examples of design of a geogrid-reinforced retaining wall, the results obtained by using the proposed method and the current method which introducing the tie-back wedge method based on Rankine's active earth pressure theory are compared. It becomes clear that the current design method is safer than the proposed design method.

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The shear strength of fill material depends on compaction condition or strain, and the tensile strength of geosynthetics depends on temperature or strain rate. It is difficult to determine uniquely design parameters for fill material or geosynthetics. Geosynthetics reinforced soil wall is a kind of hybrid structure. Hybrid structure has generally some collapse mechanisms. In design of reinforced embankment, uncertainty of design parameters and safety to every predictable collapse mechanism should be evaluated. In reliability analysis, safety of structure is estimated with considering uncertainty of design parameters and every predictable collapse mechanism. This analysis may be a useful tool to determine partial factor in limit state design. Therefore, it is necessary to establish reliability analysis method for reinforced embankment. In this paper, basic concept of reliability analysis method is proposed for reinforced soil wall with geogrid, and the effect of calculation method is examined.

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Marston & Spangler's equation is generally used to predict a coefficient of vertical earth pressure. It should be, however, separately applied to the convex type earth pressure and the concave type one. And it needs a settlement ratio not to determine easily from the experience. In this paper simple equation will be proposed to predict a vertical earth pressure ratio on the basis of the simple model that does not concern with the arch action generated around a rigid box culvert. It is proved that this equation can give a similar results with one derived from Marston & Spangler's equation and the measured data. Furthermore, since it is possible to apply to predict the reduction of vertical earth pressure by installing large compressible materials over a box culvert, the relationship between soil type and reduction effect will be estimated by the experience of deformability properties against soil classification.

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A series of shaking table tests with irregular wave were carried out to investigate the seismic stability of reinforced-soil retaining and conventional type retaining walls. In these tests, reinforced-soil retaining wall models showed a ductile behavior compared to conventional type retaining wall model. When the conventional type wall started to tilt, the subsoil reaction force at the toe of wall suddenly decreased due to loss of bearing capacity. On the other hand, tensile force in the reinforcement of reinforced-soil walls was still mobilized even if the wall tilted outward largely. Though the measured angle of failure plane and the measured seismic earth pressure became close to the theoretical values (Mononobe-Okabe theory) by considering the response acceleration of the sliding soil wedge, they didn't agree completely. This may be because the actual sliding soil wedge is not a perfect rigid body as assumed in Mononobe-Okabe theory, and the deformation characteristics of sand are different under static load and dynamic load conditions.

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Model shaking tests using an irregular base acceleration record during the 1995 Kobe earthquake was performed to investigate the failure mechanism and seismic stability of three types of soil retaining walls (RWs) situated on slope. A conventional leaning-type RW exhibited brittle failure when subjected to a relatively low base acceleration. A reinforced soil RW with a full-height rigid facing showed a coherent seismic-resistant behavior. A leaning-type RW reinforced with large-diameter soil nails at the top and bottom of RW exhibited the highest seismic-stability among the three types of RWs. The wall showed small displacements even when subjected to a base acceleration higher than 1g. This type of RW is considered as effective in improving the seismic performance of existing leaning type RWs. It was also found that the distribution of dynamic earth pressure increment could be approximated basically by a trapezoid or triangle distribution, but also depending on the input base acceleration and the pattern of shear bands developed in the foundation and the backfill.

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The preloaded and prestressed (PLPS) reinforced soil method has been proposed to substantially increase the vertical stiffness of reinforced soil structures against level II shaking. To evaluate the seismic stability of PLPS reinforced soil structures, we performed a series of shaking table tests by using sinusoidal waves having an acceleration level of 700 gals to take similarity rule into account. A fine uniform sand or a well-graded gravel were used for the backfill. The gravel backfill exhibited a much higher dynamic stability under otherwise the same conditions. The maintenance of sufficiently high prestress was found to be the key for a high dynamic stability of the structure. The use of a ratchet mechanism was found to be very effective for this purpose.

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A decrease in the prestress value by seismic load is one of the most serious potential problems on PLPS reinforced soil structures. To alleviate this problem, the best way is to set a ratchet system which keeps the prestress during earthquake and traffic cyclic loading and restrains the expansion of embankment. On the other hand, it is also important to investigate the behavior of structures during resonance. We investigated the effects of a ratchet system on the seismic behavior of the structures by shaking table tests. In particular, the behavior of structures around the resonance state was investigated.

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Geotextile-reinforced soilstructures are usually not supported with a pile foundation because of their flexibility. On the other hand, most bridge abutments and piers are RC or steel structures. This limited use is mainly due to their relatively low vertical stiffness and relatively large potential residual deformation by long-term traffic load. To alleviate the above-mentioned problem, a new construction technology, preloaded and prestressed reinforced soil method, has been proposed. The preload and prestress were applied by using tie rods of reinforced soil. To increase the seismic stability of this structure, prestress-maintaining system with a ratchet was equipped on the tie rods to investigate the maintenance of prestress and the restraint of volume of structure. We confirmed the performance of this system to do calibration test.

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The behavior of a pier during earthquake is controlled by the relationship between the natural frequency of structure and the predominant frequency of input motion. The natural frequency of a full-scale preloaded and prestressed geosynthetic-reinforced soil pier of Umaide Bridge was evaluated by measuring the particle velocity at several points of the structure by applying an impact to the structure. The results showed that the natural frequencies in the normal and to in parallel to the girder axis were found to be about 7Hz and 9Hz, respectively. The measured natural frequencies of the pier were compared with those from small-scale model tests in the laboratory and their theoretical solution. The natural frequencies of the full-scale structure, were about a half of those in the models. It is inferred that the difference between the behaviors of the full-scale structure and the scaled model is due to the different base conditions, based on the deformable ground in the field and on a rigid plate in the laboratory.

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Vertical preloading and prestressing (PLPS) of geosynthetic-reinforced soil structure aims at substantially increasing its stiffness and decreasing the residual settlement. The first prototype PLPS reinforced soil pier was constructed for a railway in 1996, and has been open to service for more than three years. Long-term measurements for more than four years have been made. It has been proven that PLPS structures are very stable for a long-term of service.
The rheological characteristics such as creep and relaxation, and the residual deformation under cyclic loading of the backfill soil and reinforcement are considered to be important factors affecting the long-term behaviour of PLPS structures. The development of theoretical models of those behaviours is essential for developing the relevant design procedure of PLPS structures. In this paper, one of three-component rheology models, named “New Isotach Model”, is used to analyze the observed load-deformation behaviour of the PLPS pier during its preloading procedure.

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Reinforced soil retaining walls with rigid facing are built by short reinforcements and cast-in-place concrete, and has already a number of actual construction results as railway embankments. Major limits of the construction method are: (1) the ratio of manual work is high, such as production, hand tamming and piling of gabions, and (2) the formwork of the facing requires much labor. Then, we used first an L-shaped welded wire net as a form-anchor of the formwork of the facing in place of gabions. In order to evaluate the practicality, we performed lateral pressure measuring tests at the time of placing concrete, and pull-out tests of a pre-support material which used the L-shaped welded wire net. In this paper, the practical performance is examined as a form-anchor of a pre-support material based on the field tests. Consequently, it has been confirmed that a lateral pressure approximately equal to water pressure acts temporarily and partially when concrete is cast, and that a pre-support material has a pull-out resistance to withstand the lateral pressure.

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The arched-structure has been utilized to a lot of structure since ancient times. It is known that those structures resist by it's substituting compression power for upper load.
As the construction materials, stones, concrete and stiff materials have been used mainly. On the other hand, it is confirmed that “soil bag” which is wrapped soil with geosynthetics displays big compression by restriction effect of geosynthetics. Therefore, loading laboratory test which used soil bag that wrapped a layer system mass of aluminum stick with paper for calligraphy was carried out, because it is thought that the tunnel lining to build in embankment can utilize to the arch structure using this soil bag.
Because an arching effect by soil bag was able to be confirmed from this model test result, two arched-structures of actual size of inner wide 5m were built with a purpose to confirm actual behavior and execution.
In this examination, the transformation and the behavior of earth pressure were confirmed during the construction of arch structure of inner wide 5m. As a result, the possibility of the construction of arched-structure and that stress concentrated on the inside of arch were confirmed.

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As a protection retaining wall to catch a landslide, a debris flow and falling rocks, stiff structures of concrete retaining walls is used mainly. There are many advantages when the embankment reinforced with geosynthetics is used as a protection retaining wall. The correspondence of the embankment utilizing surplus soil structures harmonized with naturally can be built, at the place where a geographical condition is bad.
At a present, when pseudo static load or shock power acted to embankment reinforced with geosynthetics, the availability watched from volume of deformation and destruction strength is indistinct. This paper reports a result of field loading test that pseudo static load is given to the reinforced embankment, and also reports the inspection of the effect on reinforced embankment. The experiment carried out two kinds of small model experiment of 1.5m high and actual size model experiment of 6m high. Static load was added from a horizontal direction.
Loading test was also done about the reinforced embankment given compression power by prestress in order to prevent separation of a top and bottom direction of embankment. In this experiment, displacement and inside stress of reinforced embankment, and stress to act on geosynthetics was measured.

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The retaining reinforced soil wall of Rock-fall protection has been developed for a few years. It need some spaces to construct by it's structure and also there are often few spaces to construct the wall where need to such a protection structure. Therefore the pocket type reinforced soil wall of Rock-fall protection was developed. It can be constructed in narrow space at a roadway side and it can catch a rock by it's top. This paper describes the experimental research of the reinforced soil wall for rock-fall protection. The experiment was performed two models of prototypes, the miniature size model (wall height 1.5m) and actual size model (wall height 6.0m). The experiment of miniature size model was confirmed the effect of geo-grid. And the experiment of actual size model was confirmed behavior the wall when at the moment of collision the rock and it's safety against a huge scale rock fall

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