Deformation reinforcement theory (DRT) advances stability criterion for elastoplastic structures and suggests effective reinforcement to prevent instability. The core of DRT is the principle of minimum plastic complementary energy (PCE): elastoplastic structures deform trending to the state of minimum PCE, or to take full advantage of their bearing capacities while to minimize the required reinforcement. This principle is rederived and the principle of minimum complementary energy for stable states is given. It is shown that DRT promotes finite element method by revealing the physical meanings of the unbalanced force and the modified Newton-Raphson algorithm. By comparison with the rigid body limit equilibrium method, the engineering significance of DRT is illuminated: the traditional action-resistance system in engineering design is extended to action-resistance-reinforcement system, where reinforcement fully described the difference of action and resistance.

The stability of roof is the main factor to determine the roadway section size in the underhand slice stoping with cemented filling method. The failure modes, deformation characteristics of cemented tailings backfill roof and mechanical characteristics of reinforcement are studied by similarity simulation and in situ monitoring according to the actual conditions of Wushan copper mine. The experiment of similarity simulation indicates that the failure mode of roof is not affected by the arrangement of reinforcement in the cemented tailings backfill. And in comparison with the horizontal arrangement of reinforcement, the vertical arrangement is more helpful to enhance the overall stability of roof. In situ strain monitoring results show that the distribution of strain state of filling body roof is more complicated compared with the computation result of simply supported beam. In vertical direction, filling body roof is tensile strain. However, tensile and compression strains alternate with the mining process in horizontal and along roadway direction. Relationship between load on reinforcement and time is obtained by monitoring results of 24 reinforcement metres. According to the mechanical characteristics of reinforcement with the mining process, the process could be divided into four stages: i.e. initial tensile stage, relatively stable stage, alternant stage of tensile and compressive states and the bearing stage. In the bearing stage, reinforcements in the roof bear against the maximum compression before roadway is mined. And after the roadway under the roof has been mined out, reinforcements bear the maximum load of tension and show suspension action. The maximum tensional area lies in the crossing roadway roof.

In weak rock tunnel, elimination of systematic rock bolts is advanced, and the primary support structure is the combination of steel arch, shotcrete, reinforcing mesh, feet-lock rock bolt and longitudinal link steel bar. This paper is based on Baojiashan tunnel. Two test sections are chosen and field test is carried out. With systematic rock bolts replaced by feet-lock rock bolts, two models of systematic rock bolts and non-systematic rock bolts are established and analyzed comparatively. The content of comparative tests includes: the clearance convergence of tunnel primary support, surrounding rock pressure, steel arch stress, shotcrete stress, axial force of rock bolt and longitudinal link steel bar stress. The result shows that the deformation of primary support in the two test sections tends stable and the structure is safe, which shows that the elimination of systematic rock bolts does not affect the security and stability of primary support; some rock bolts in the arch part are subjected to tension; and some are subjected to compression; but the force is minor, and the maximum tensile stress is only 11.8% of ultimate strength of steel, so the support action of rock bolts in the arch part is not obvious; most feet-lock rock bolts are subjected to tension, and the maximum tensile stress is up to 191 MPa, so the feet-lock rock bolts play an important role in the support system. The elimination of systematic rock bolts will reduce construction process, lower engineering cost and shorten procedure cycle time, which is conductive to an early closure of surrounding rock to form a complete supporting structure. It will get a significant economic value and social benefits.

By using Lode angle, a shape function is proposed to describe the curve of strength criterion in octahedral plane, and then the Mohr-Coulomb criterion is revised to predict the influence of the intermediate principal stress ratio on the peak friction angle of soils correctly. The revised strength criterion is shown to be able to produce the same curve with Lade-Duncan’s criterion in octahedral plane, while it is suitable for predicting the strength of loose sands under true triaxial condition. In the loading process, the deformation of soil body often accompanies with strain localization, which makes the mobilized strength of soils to be reduced. The reducing effect on the strength of soils by strain localization is justified by bifurcation analysis. By comparing to the experimental results, it is shown that the mobilized strength of dense sands can be correctly predicted by the bifurcation analysis of non-coaxial plasticity under different intermediate principal stress ratio conditions.

Scanning electron microscope (SEM) was used to observe microstructure of soft clay before and after shearing under complex stress path, which analyzed microscopic nature on anisotropy of normalized shear strength of intact soft clay in three respects including changing characteristics of pore arrangement, changing characteristics of pore pattern and changing characteristics of pore scale. Test results revealed that the pore arrangement was disorder before and after shearing, and changes of pore orientation were very small, which influenced very little on macroscopic properties of clay. Changing characteristics of pore pattern contributed significantly to anisotropy of normalized shear strength of clay in coefficient of intermediate principal stress equal to 0. Changing characteristics of pore scale contributed significantly to anisotropy of normalized shear strength of clay in coefficient of intermediate principal stress equal to 0.5. Therefore, the micro-change factors which influenced anisotropy of normalized shear strength of clay after shearing were different in different coefficients of intermediate principal stress.

Wind erosion failure law of aeolian soils subgrade and the influence of the different subgrade design cross-sections on wind-blown sand are studied through interior wind erosion wind tunnel test. The wind-blown sand’s process of disturbance, accelerating, speed-down, and recovery in different subgrade cross-sections are studied; the characteristic of wind-blown sand field around subgrade are summarized for subgrade defect and subgrade non-defect. The influence factor on the wind erosion failure of aeolian soils subgrade is analyzed. The results indicate that the effect of subgrade height and slope gradient on the wind-blown sand field is obvious; while the change of subgrade’s width can’t affect the flow field notably. The disturbance to the flow field enhances with the increase of subgrade’s height, blow erosion on the top of the windward slope is severe; and heap erosion destroy is brought to the bottom of leeward slope. When subgrade model height is 250 mm compared with that of 60 mm, the wind speed on the top of windward slope increase 1.13 times and decrease 2.53 times at bottom of leeward slope for the certain side slope rate. So subgrade height should less than 2.5m to avoid the wind erosion failure of desert highway. Further, the influence of the different side slope rate on wind-blown sand is analyzed for the certain subgrade height. The change of the wind speed is unconspicuous when the side slope gradient is 1:1.75, the wind erosion failure of aeolian soils subgrade is neglectable.

A lot of on-site monitoring results show that the soil around many underground constructions is still in a state of small strain under working loads. It is important to consider the soil’s small strain stiffness and stress-path dependency in analyzing interaction between soil and structure. Hardening soil model can define loading-unloading characteristics, however, it can not accurately simulate nonlinear modulus because unloading-reloading modulus is not associated with stress and strain level. In this paper, unloading-reloading modulus of hardening soil model is modified so that it is related to both stress and strain levels; and unloading shear strength and scant stiffness of lateral unloading stress path are also considered specially. Finally, the model results are compared with soil stress-path test results to prove the reasonableness of the model.

A series of tests were done to study the influences and variation of strength of a single kind of expansive soil in the process of changing the soil state from nature and unsaturated and no cracks to saturated and no cracks to saturated and cracks fully developed by shear test and triaxial test. Test results show that water content and density and cracks influence the expansive soil strength; and water content and cracks influenc strength more than density does. It is concluded that cracks should be considered within the method of determining expansive soil strength. It is suggested that the strength of sample after 5 cycles of wet-dry should be used as the strength of cracks fully developed expansive soil. By residual strength tests, a conclusion is drawn that the residual strength of expansive soil was in proximity to the strength of cracks fully developed expansive soil; as a result, the residual strength could be used approximately as the strength of expensive soil in the region of cracks developed.

The asymptotic expansion method was combined with micro-based statistical model to develop a two-scale scheme for analyzing the behavior of brittle rock. The material properties were defined in micro-scale and the elastic-perfect brittle constitutive was adopted, the modified Mohr-Coulomb theory and the maximum tensile strength were selected as the fracture criterion. Through calculating in a global-local coupling way, the damage evolution of material in the micro-scale and its effects on the properties of rock in the macro-scale were derived. The scheme included three steps: determining material statistical parameters, determining representative volume element (RVE) and solving boundary equations. The numerical model was realized by the commercial software ABAQUS and its subroutine UMAT. This scheme can be used in the conditions that the rock is loaded with uniaxial compression or triaxial compression with low confining pressure. The regularization method is not used, so the result is mesh dependent after the rock is localized.

In many practical situations, for instance, in jointed rock mass, linear M-C yield criterion may not be justified and a nonlinear Hoek-Brown yield criterion would be more appropriate, so it is necessary to attempt to calculate deformation of tunnel by the criterion. The surrounding rock is divided into three zones: elastic zone, strain softening zone and plastic flow zone. Theoretical derivation on deformation is carried out by Hoek-Brown criterion and non-associated flow rule. Parameters of surrounding rock in strain softening zone are variable and they depend on the plastic deformation of this zone, so it’s difficult to derive the analytical solution for stress in this zone. Runge-Kutta method is used to carry out numerical calculation and the radiuses of strain softening zone and plastic flow zone are calculated. Finally, the deformations of tunnel are calculated. It is demonstrated by an example that the results calculated by the method in this paper and Carranza-Torres’s method are almost the same when strain softening zone and plastic flow zone are not be considered. Furthermore, it is demonstrated by the other example that dilation angle affects deformation more severely when in-situ stress becomes greater.

Two groups of parameters of ellipse-parabola double yield surface model from consolidated drained triaxial tests are used to study the influences of stress-strain relationship by changing one of parameters ? , KG, n, h, m, M1, M2 and pr (keeping other parameters constant). It is found that the volume strain is evidently sensitive to the parameters of h and m. On the other hand, ? , KG and n have significant influence on the volume strain for a dilative soil but little influence for a compressive soil. Parameters of ?, KG, n, h and m have no influence on shear strength that is reflected by the double yield surface model. The parameter pr has little influence on the volume strain and shear strength. In the opposite, parameters M1 and M2 affect the volume strain and shear strength dramatically; and the smaller one determines the strength in the double yield surface model. A parameter, called sensitivity which reflects the influence of model parameter on the stress-strain relation, is defined. It is found that different parameters give quite different sensitivities; and different soils also result in different sensitivities. It is pointed out that more attention should be paid to the parameters with high sensitivity to stress-strain of soil.

In order to decrease the blasting damage to tunnel surrounding rocks, a new charging structure and its mechanism are proposed based on the traditional smooth blasting charging structure. The PVC-U material is placed beside the burn-cut cavities to protect the surrounding rocks of the tunnel. The Φ100 mm Hopkinson test equipment is used for the purpose of researching the weakening level of the PVC-U pipe. The analysis is made on macroscopic damage of the test sample, attenuation of stress wave and dissipation of energy respectively. The test results show that: the stress state of rock is changed by the protective layer and the damage of the rock without protective layer is worse than that with the protective layer; and as increasing of the thickness of protective layer from 0 to 6.24 mm, the degree of rock damage decreases; the stress peak shows decreasing trend; and the reduction rate of peak stress value increases instantly. The ratio of dissipation of energy and the incident is reduced from 61.08% to 39.97%. Thus the conclusion can be drawn that the impact damage of rock is protected by the protective layer. Good results have been obtained in a roadway excavation project.

At the background of zonal disintegration was found in the model test, the strain field of the circular tunnel was studied by using the classical Fenner formula. The discontinuity of the radial strain and the concentration of elastic deformation energy were found at the ultimate balance boundary. The formation of the circular crack which is concentric to the opening is the rupture and separation between the ultimate balance zone and the elastic zone caused by the discontinuity of the strain field. Zonal disintegration is the result of ultimate balance zone expanding to deeper rock mass after the separation. The analysis results explain the non-monotonic under changing laws of the strain and displacement in surrounding rock mass with the distance to the cavity increasing; and the formula of radius of the fractured zones was got and it showed that there exist the equal ratio relations between the radiuses. The value of it was corresponding to the geostress state and the parameter of the surrounding rocks. Taking the parameters in the model test into the formula, it obtained that n =1.1. It matches well with the shape character of the fractured zones in the disassembled model after test.

Groundwater has mass corrosion pollutant because of environmental pollution that has a strong impact on the strength and durability of soil-cement subgrade. The soil-cement blocks has been soaked in different concentrations of vitriol solution for various ages in the laboratory. After testing electric resistivity and unconfined compression strength, the effects of vitriol pollution on soil-cement electric resistivity are presented. The results indicate that the electric resistivity of soil-cement and pore water are decreasing with the increment of vitriol solution concentration while increasing with the increment of age; the formation factor is increasing with the increment of vitriol solution concentration and age; the unconfined compression strength of soil-cement blocks is increasing with the increment of soil-cement electric resistivity. Finally, a formula is purposed to forecast soil-cement electric resistivity at any solution concentration and age.

To better understand the in-situ engineering conditions of frozen ground where the piers of Qinghai-Tibetan ±500kV Direct Current Transmission Line Project will be constructed; the direct shearing creep experiment for frozen silty clay, a kind of soil taken from Wudaoliang on the Qinghai-Tibetan Plateau and remodeled in different moisture contents and densities in laboratory at -2℃, was carried out. The study results show that most creep of the frozen silty clay appears as attenuation creep which has two phases: unsteady creep phase and steady creep phase; only several creeps of frozen silty clay takes on the third phases: accelerated creep phase. The long-term strength of frozen soil could be calculated by the long-term strength equation. The long-term strength of the frozen silty clay closely affected by the moisture content and density of the soil; the frozen soil with higher moisture content has higher long-term strength at low moisture circumstance; but it shows opposite trend at high moisture circumstance; the frozen soil with higher density has higher long-term strength with the same moisture content.

In recent years, with China's social and economic development, more and more cities began to plan and build metros. Meanwhile, the metro construction encountered the sandy pebble soil in some cities, especially the running tunnels of Chengdu Metro line 1 and 2 are almost both need to cross the sandy cobble soil. According to the design, Chengdu metro No.1 and No.2 lines will be constructed by mudding-type earth pressure balance shield. And during shield tunnelling, the face stability control that will be a key operation to ensure the construction can be carried through smoothly. Nowadays, the study of supporting earth pressure is mainly focused on sandy and clay soil; but the study involving the face movement and collapse of cobble-soil is seldom. So based on the heavily discrete characteristics of cobble-soil, the paper analyzes the shield tunnel face deformation and failure while the support pressure is lower than the limit pressure which constructed by using earth pressure balance method and the deformation and failure of excavated face by discrete element method. The results show that: (1) supporting earth pressure of tunnel face is lower than earth pressure at rest; (2) after the face loses stability, the slider ahead of the tunnel face is a surface body. The results will give reference to determine the face control pressure of shield tunnelling.

The causes of piping and sand boiling of shield launching are analyzed; a model that groundwater permeates from reinforced soil pervious underlying layer to wall is established. Using semi-confined aquifer seepage theory, an example is given to demonstrate that, supposing that the reinforced soil is impervious, the accident that water and sand inflows from tunnel portal is influenced by range of soil reinforcement, groundwater level and the gap of wall; the cost and safety of engineering have the positive correlation with the length of reinforced soil; the depth of reinforcement isn’t so deep but reasonable; the gap of wall also plays a key controlling role to shield launching’s safety. The factors are mutual constraint; construction parameters are influenced by security, economy and time limit for a project.

It is of common occurrence that the flood scours the riverbed and the back-silting takes place immediately by turn, which inevitably influences the safety of shield tunnel through the Qiantang River. Hence, how to determine the thickness of covering layers reasonably is an urgent problem to be solved to ensure the safety of tunnel and the construction cost under control. According to the completed study that the riverbed thickness decreases extremely by nearly 16 m after the heaviest flood in 300 years, two embedding schemes of subway line are selected initially. That is, the minimum overburden layer thickness of tunnel is 3.5 m or 4.0 m. The results show that the two schemes are both safe for the tunnel considering the shearing effect of the soil around the tunnel and the one of the bolts between rings. However, in construction, the possibility of floating upward for shield tunnel increases greatly under the buoyant force action of back-filled grouting. More attention should be paid to construction management to minimize the disturbance of soil around the tunnel.

Recently, stabilization/solidification of heavy metals contaminated soils (HMCS) using lime, cement, and other binders has been widely adopted in geoenvironmental engineering practice. In this paper, the mechanisms of heavy metal-soil-binder interaction are overviewed based on literature studies. The performance of various leaching test standards for solidified HMCS is compared and discussed. The unconfined compression strength properties and influencing factors of solidified/stabilized heavy metal contaminated soils are also presented. The leaching properties, durability and long-term performance of HMCS from domestic and international studies are summarized. Finally, based on the current studies in China, it is suggested that the minimum strength requirement of HMCS should be given; and test specification of dynamic leaching tests should be built as the assessment criteria of contaminated lands remediation.

Based on the scheme of underground excavation of tunnel in Qiushui mountain, a finite element model of a shallow buried tunnel beneath an expressway in soft soil region is established, so as to evaluate the effect of tunnel excavation on the expressway above. Considering the minimum embedded depth of the tunnel which is only 4 m and vehicle load on the surface ground of the expressway, a method combined new Austrian tunneling method(NATM) and umbrella arch method(UAM) is put forward in the design. Analysis is performed using plane strain finite element model, which shows the characteristics of NATM by using stress release steps and tracing element. The UAM is simulated by using coupling constraint and spring element. The excavation sequence and support sequence are also taken into consideration in the analysis. As a result of this study, controlling the lateral deformation of the tunnel lining can reduce the settlements of ground surface effectively during excavation; and the method combined NATM and UAM is applicable to shallow buried tunneling especially in soft soil region.

As shield tunnelling method is applied widely, the longitudinal uneven settlement of shield tunnel has emerged because of the comparatively large settlement after construction, and the designing method has been emphasized gradually, which can consider the longitudinal structure characteristics of shield tunnel. For the purpose of determining the longitudinal equivalent bending stiffness, a 3D calculation model has been established, considering the longitudinal bolts’ characteristics and the ring seams’ true splaying states. The results show that some factors related to the ring seam, for example the amount of longitudinal bolts, the assembly pretightening force and segment ring width, influence the longitudinal bending stiffness largely, which increases linearly with the amount of longitudinal bolts and the segment ring width, and which nonlinearly increases with the assembly pretightening force. Other factors related to the longitudinal seam, for example the transverse effective rigidity ratio, influence it less. The results provide key parameters for the longitudinal design method of shield tunnel.

The increment of sodium montmorillonite crystalline interspace caused by tap water is greater than KCl, NaCl, CaCl2 solutions with different salinities; adding different types of salts into water can stabilize sodium montmorillonite clay mineral and inhibit the expansion of crystalline interspace. The increments of crystalline interspace affected by different salinities and types of solutions are different. Comparing three kinds of solution KCl, NaCl, CaCl2, the variation caused by KCl solution is the least; the crystalline interspace variation is only 1.32% under the saturated KCl solution. When sodium montmorillonite contacts with different types of solution, the crystalline interspace increment decreases and gradually tends to be stabilized with the increasing of solution dosage. The hydrate expansion capacity of sodium montmorillonite has no direct relationship with the total solution dosage; when the clay mineral is soaking in water, interspace will not expand unlimitedly as the increase of the total volume of water. When contacted with the same dosage but different types of solution, the crystalline interspace changes as complex exponential function with the increase of contact time; in shows the characteristic of mutation increasing in the initial stage and quickly tending to be stabilized.

The environmental effect of soil contamination recently has aroused considerable public concern since the increasing soil pollution, however, less attention was given to engineering properties of contamination laden soil. Therefore, the influences of sodium dodecyl benzene sulfonate on the mechanical characteristics of loess have been investigated by the authors. It has been proved that the pollution can weaken the loess, reducing cohesion, compression strain and permeability, as well as limiting collapsibility. Moreover, the contamination mechanism towards soil mechanical characteristics was discussed with the assistance of scanning electron microscope in junction with the soil water characteristic curve. It is necessary to prevent the deteriorated effect of anionic surfactants on the loess in the engineering in future. Simultaneously it could be applied to reducing the collapsibility of loess.

If acceleration of rock mass is too large, the surrounding rock of underground cavern is not stable. By analyzing time-history curves of acceleration obtained by model test, the acceleration response characteristics of surrounding rock with different anchorage parameters in underground cavern subjected to explosive loads are studied. The forms and peak values of the time-history curves of acceleration of underground cavern’s crown, floor and two sides are explained respectively. Because of the different reinforcing modes, the distinctions of the acceleration response of surrounding rock of underground cavern are compared emphatically. The results indicate that the time-history curves of the vertical acceleration of crown and the horizontal acceleration of floor right side are smooth enough; but the vibration of the time-history curves of the vertical acceleration of floor and the left side are larger than the others. The acceleration of the crown is the largest than the other positions. For the cavern of the smallest spacing of rock bolts in four underground caverns, the acceleration of its crown and two sides is smaller than the other caverns; but the acceleration of its floor is larger slightly than the others’. By means of comparing and analyzing above, reducing the spacing of the rock bolts can enhance the stabilization of underground cavern.

Computation of earth pressure acting on retaining structures constitutes an important research subject in the field of geotechnical engineering. In many engineering practices, the retaining wall displacement causing the backfill yield sufficiently cannot take place so that the earth pressure may fall anywhere between active and passive earth pressures. Besides, due to compaction, the backfill is always dense and its shear resistance will decrease from peak resistance to residual state during shear. However, classic Rankine and Coulomb earth pressure theories can only evaluate the earth pressure at the active and passive state. And they cannot consider the effect of reduction of post-peak shear soil resistance on earth pressure. The development of earth pressure at the passive side with wall displacement is studied. On the basis a new methodology is developed to evaluate earth pressures at the passive side under any boundary strain constraint for a rigid retaining structure with translational movement. It can take into account the effect of wall displacement and the strength characteristic of dense sand on earth pressure. The agreement of calculated results with the experimental ones confirms the correctness of the proposed method.

The researches on the quantitative analysis of ground settlement induced by the shield tunnelling workmanship are relatively less. In this paper, three workmanship parameters, i.e. grouting filling ratio, shield pitch ratio and support pressure ratio, are introduced into the gap parameters to make the quantitative analysis of ground settlement based on Loganathan expressions. The deep discussion about the equivalent circle zone which was proposed by some scholars is made to provide the basis of numerical analysis for the shield tunneling project. The back analysis of the Xi’an metro line-2 is carried out to validate the rationality of the method introduced in this paper. It is shown that the method can factually reflect the workmanship level and offer a certain reference to the control of the ground settlement during the shield tunneling.

Based on the Xi’an metro shield tunnel traversing old loess strata, dynamic tracking measurements of water pressure, earth pressure and structure internal force (axial force and bending moment) are carried out to analyze influences of the shield tail serum injection, cylinder thrust force, soil stress relaxation and water pressure on the distributions and varying laws of segment ring. Combining with field test data of internal force, the distribution mode and value of the load pressure on the segment lining in old loess strata are back analyzed by using orthogonal design method and defining target function. Internal force which are calculated by using optimized design parameters are quite close to measured value in magnitude and distribution. The results show that the analysis method proposed is feasible and reasonable; so it can be used for reference of similar projects.

Because of different compositions and depositional environments, the natures of dredger fills are different. In this paper, Tianjin marine soft soil is used as material to simulate site environment to study the strength growth in soft dredger fill. Experiments show that the different conditions of pressure and drainage affect the growth of soft dredger fill greatly. When conditions are conducive to the drainage of water in soil, the growth of strength is significant. The effect on soil strength growth by overburden pressure is through some possible drainage; when drainage conditions are bad, and the pressure increased, the strength grows slowly and little; on the contrary, it grows faster and absolute value is large.

The dynamic responses of a pile foundation under hammer impact are analyzed. The concrete pile in soil is modeled as a (standard linear solid) viscoelastic rod buried in a (Voigt-type) viscoelastic media. The upper end of the pile is subjected to a mass impact; and lower end is supported by a spring-dashpot foundation. Governing equations for the pile movement are given. Coupled boundary conditions at the upper and lower ends are deduced respectively using the dynamic equation for the hammer and the constraint equation for the foundation. The initial-boundary value problem is solved by using Laplace transform with respect to time variable to the equations. An exact solution for the stress distribution in the pile is obtained in the transformed domain. Using numerical inversion technique the stress-time curves at any sites of the pile can be calculated. Examples are given to show that the approach can be conveniently applied to analyzing the generation, propagation, reflection and interactions of the viscoelastic stress waves in the pile.

n view of old landslides, four kinds of indices including nine secondary factors, i.e. landform characters, slip surface characters, landslide body structures and recent activities signs, were chosen as the discrimination indices for potential landslides. According to discriminant analysis theories, distance discriminant analysis(DDA) models and Fisher liner discriminant analysis(FLDA) models were respectively built for potential landslides in the Three Gorges Reservoir and the upper Minjiang River areas based on the same number of training samples. The results show the error rates of DDA method were both 0% for testing and training samples, while the error rates of FLDA method were respectively 11.1% and 0% for testing samples and 5.56% and 11.11% for training sample in the two study areas. So, DDA method has much higher prediction accuracy than that of FLDA method for discrimination of potential landslides in the two study areas.