Finite element method of the internal friction angle and saturation degree with the groundwater levels variations

In recent years, research on the internal friction angle was done by previous researchers. The research objective shows the relationship between water content, porosity, saturation, internal friction angle, and the vertical displacement of the ground with depth variations. The experiment and numerical model were used for comparison by Viet Nam’s standard “TCVN 4196: 2012” and the finite Element Method (PLAXIS 3D software). Results show remarkably water content (W%) and porosity (P%) at the maximum value of 94.35% at 4.8m depth, whereas the minimum value is 18.22% at 39.3m depth; which compared with porosity (P%) of 71.9% at 4.8m depth, and 40.4%. On the other hand, saturation results presented 88.09% and 86.79% at the center of the grounds. The increase of 23% and 75.42% (from 18.3m to 39.3m). Moreover, the vertical displacement maximum value of 0.01975 m (z = -36.9m) depth with ϕ 0 = 290); whereas the minimum value is 0.002844 m (z = 0m) depth with ϕ 0 = 20. The mean value at the center of the Clay layer was obtained at 0.0577m, and 0.0156 m at the Sand layer. From these research results, civil and geology researchers, scientists, and so on can use the best references for their works.


Introduction
Research on the vertical displacement of the ground was determined by many different methods and materials from the previous results.Research on the role of soil inherent anisotropy in peak friction and maximum dilation angles of four sand-geosynthetic interfaces was done particularly, results show a residual friction angle is obtained for each interface type as the inclination angle of the plane becomes bedding (Afzali-Nejad et al., 2018).Investigation of the Interaction of rigid shallow foundation with dip-slip normal fault rupture outcrop: effective parameters and retrofitting strategies, results show the foundation surface was displaced by the increasing friction of the granular soil (Ashouri et al., 2022).Evaluating the Nγ coefficient for rough strip footing located adjacent to the slope using the stress characteristic method, the results presented show that the friction angle decreased as the crude oil was added to high clay quantity (M.Ahmadi et al., 2021).On the other hand, an asteroid regolith strength: Role of grain size and surface properties was done carefully, results described the increase in the angle between 25 and 45 as the strength increased between 600 and 900 Pa, and bulk cohesion values between ~ 400 and 600 Pa (Brisset et al., 2022).Measurement of the causes of the high friction angle of Dutch organic soils, results were done particularly the highest of φ′ value was corrected by the effective pressure is low (Cheng et al., 2007).
Moreover, in the research on the Responses of calcareous sand foundations to variations of groundwater table and applied loads, results presented the sand particles were not returned the same as the initial shape as the increasing friction angle (Cao et al., 2014).A numerical model of the Application of slightly overlapped circular particle assembly in numerical simulation of rocks with high friction angle has shown in particular, results presented that the shapes of the particles were irregular as the friction angle is higher (Fakhimi, 2004).Moreover, an Investigation of the correlation between the fractal dimension and internal friction angle of different granular materials was done, the results presented the general relationship that links the friction angle and structural fractal dimension is qJ = 109.83D2-89.362(Gori & Mari, 2001).Evaluation of the effects of spatial autocorrelation structure for friction angle on the runout distance in heterogeneous sand collapse is described carefully, and the results show the distance increases with the increase in COVφ (Ma et al., 2022).The study on the empirical correlation between penetration resistance and internal friction angle of sandy soils described in particular, results presented the value of friction angle was set up particularly as sandy soils are with N1 from 3.5 and 30 (Hatanaka & Uchida, 1996).Measurements of hypoplasticity for soils with low friction angles are presented carefully, and the results show the friction angles (ϕ) of "Janerio clay" were set up by the hypoplastic model as the increase of loading (Herle & Kolymbas, 2004).The evaluation of the strength and deformation properties of frozen sand under a true triaxial stress condition is presented, in particular, the results show the strength, elastic modulus, and friction angle increased in b from 0 to 0.6 but decreased with b from 0.6 to 1 (Huang et al., 2022).
In contrast, the evaluation of the effect of one cycle of heating-cooling on the clay-concrete pile interface shear strength parameters was carefully evaluated, and the results were done, particularly the residual interface friction angles at the peak, by a percent range from 13.6% to 35.5% (Idries et al., 2022).The measurement of stability numbers for an unsupported vertical circular excavation in c-/soil presented particularly the computational results are generated up to height/length (H/b = 10 and = (ϕ) 40° (Kumar & Chakraborty, 2012).The research on the probabilistic study on the bearing capacity of strip footing subjected to the combined effect of inclined and eccentric loads was done, particularly when the friction angle was ϕ = 40•, COV tanϕ = 10%, δx/B = 10, and δy/B = 0.25, whereas the increase in e/B values from 0 to 1/3 for α = 0• results in 87.7% reduction in the magnitude of μNγ values (Krishnan & Chakraborty, 2022).The measurement of evaluation of common practice empirical procedures for residual friction angle of soils: Hawaiian amorphous material rich colluvial soil case study has done particularly well, the results presented carefully the residual friction angle presented poorly with the colluvial soils as its richer than in amorphous materials (Kaya & Kwong, 2007).Evaluation of the related equal smectite content and basal spacing to the residual friction angle of soils was done carefully, the results show the smectite content of soils controls their ϕ′r, which increased from 5% to 16% and causes the shear to slide (Kaya, 2009).
In contrast, in investigation of the micromechanical tangential force measurements between tetrahydrofuran hydrate particles described carefully, the results described particularly the macroscopic scale reported temperature at time <30 seconds, and the friction angle is nearer than that of the plane (Q.Luo et al., 2022).The research on the scale and water effects on the friction angles of two granular soils with different roughness is evaluated in particular, the results presented particle-scale tests evidenced higher inter-particle friction for DNA-1A in wet conditions with respect to the dry case for normal force lower than 2-3 N (Marzulli et al., 2021).The evaluation of the effect of particle size of sand and surface properties of reinforcement on sand-geosynthetics and sand -carbon fiber polymer interface shear behavior is presented, in particular, the results show the friction angle for SM2 soil was 16% and 28.3% higher than that for SM1 and SF soils, respectively (Namjoo et al., 2020).
The novelty of this experiment method used the collective data of the internal friction angle and saturation values in the laboratory at different depths and used the Plaxis 3D software to credit the vertical displacement of the internal friction angle and saturation at the different depths; whereas some of the previous research did not present clearly.

Soil properties
The research areas were done at the three boreholes "HK" which include "HK1, HK2, HK3" from+2.0m to −40.0 m depths with latitude 10°09"35"' North and 104°58"39"' East of the My Thai Canal Bridge, Hon Dat town, Kien Giang province, in Viet Nam.Field surveying and experiments in the Laboratory have been done carefully by the Viet Nam Standards TCVN 4196: 2012" and TCVN 4202:2012 (see Figure 1).The groundwater level is at 0.0 m.
Field experiments were implemented by the Standard Penetration Test "SPT" at depths from+0.0m to −40.0 m.The Ground is divided into small seven layers (Layer 1a; Layer 1; Layer 2a; Layer 2; Layer 2b; Layer 3 and Layer 4) and the soil characteristics show in Table 1 (see Table 1).In this research, the ground is divided into two big layers, which include a "Clay layer" from 0.0 m to 27.0 m depths, and a "Sand layer" from 27.0 m to 40.m depths.

Water content (Humidity) W% with the different depths (m)
Samples were collected and protected carefully from the Field to the laboratory before doing the following experiment measurement process.The sample sizes show 30 × 50 cm and cobble materials.The total of the samples is 12 samples for each borehole.The soil was sieved through sieve diameters 0.005 mm; 0.1 mm; 0.25 mm; 0.5 mm (Clay soil); whereas 0.14 mm; 0.315 mm; 0.63 mm; 1.25 mm; and 2.5 mm (sand soil).These soil samples were kept in a sealed box after 24 hours of moisturization to ensure compositional homogeneity.The temperature in the laboratory is at 26°C.Using 80 grams of soil mixed with many different water contents (wet soil), which included 2%; 5%; 8%; 10%; 15%; 20%; 25%; 30%; 40%; 50%; 60%; 70%; 80%; 90% and 100%.After finishing mixing, the soil samples were protected in the sealed box within 24 hours.And then soil samples were moved to the oven at a temperature of 105°C within 24 hours (dry soil).Results have been recorded carefully one by one of the initial values (wet soil) and the final values (dry soil) to obtain the best results.

Porosity (P%) with the different depths
The soil was used at 150 grams and determined with the initial total volume "Vt."The soil was dried in the oven at the temperature of 1050C until the temperature is constant after 24 hours.The soil was poured into the cylinder sample and cobble material with a diameter size of 30 × 50 cm "Vb."And then this sample was compacted without even leaving only solid particles "Vp," and vacuumed and all the air is sucked out and collected in the other bottle, which contains air with volume "Va."Measurement of the solid volume "Vp," which equates to the air volume "Va."The results show the Porosity (P%) = the solid volume "Vp"/the initial total volume "Vt."The other results can be calculated by equation 5 and Table 3.

Saturation (S%) with depths (m)
From the determination results of the porosity, it is easy to determine saturation by reusing the same method as the determination of the porosity.Saturation was calculated by the equation as S% = (V w /W h )*100%; whereas V w is the volume of the water.The remaining results were calculated in the equation 3 and Table 4.

The internal friction angle (ϕ 0 ) variations with the different depths
The samples are saturated completely after 24 hours.For all of the samples with size 60 × 60 mm that are put in a shear machine, the time for the cutting process is 0.005 mm/minute.The Direct Shear Test experiment was done at three boreholes "HK1, 2, and 3" and the different depths.The Loading is designed in this process 0.25 kg/ cm 2 ; 0.5 kg/cm 2 ; 1.0 kg/cm 2 ; 1.25 kg/cm 2 ; 1.5 kg/cm 2 ; 2.0 kg/cm 2 ; 3.0 kg/cm 2 ; 4.0 kg/cm 2 .The specification of the machine is shown in Table 2.

Saturation and suction matric variations
a) At the depth from 4.0 m to 27.0 m (Clay layer) The percentage of particles that can be gone through sieve #200 was 42.74% and the Plasticity Index was shown at 20.87.So the value "wPI" = (42.74× 20.87)/100 = 8.92%, which is described the line 10 (it means "wPI" = 10).Moreover, the value  "wPI" = (percentage of particles, which can be gone through the sieve #200), which was shown as (a decimal) x (Plasticity Index).

Numerical model of the internal friction angle variations and saturation with the different depths (Brinkgreve R. B. J (2014)
a) Boundary conditions, assumptions, and limitations in the simulation (see Table 3) The PLAXIS 3D software (the finite element method) is designed by the Mohr-Coulomb theory model, which involves only five basic parameters (E,' ν,' φ,' ψ').The boundary conditions of the model are set up to ensure that the model can work safely and exactly.
On the other hand, the assumptions of the model with the maximum size (length x max = 7.5 m; width y max = 7.5 m; depth z max = 75 m).This permits any possible mechanism in the clay field and avoids any influence of the outer boundary.In this case, the building is considered to have a stiff structure and links in the form of movable and fixed pillows.The ground shows full of Clay layers (from 0.0 m to 29.0 m); whereas depths are presented from 29.0 m to 39.6 m for Sand layers.The soil stratigraphy parameters are shown in Table 3 (see Table 3).The groundwater level is at+0.0m, and the measurement of the depth of the groundwater levels will change from 0.0 m to −4.0 m.The model keeps the default units in the Units that include "Length = m;" Force = kN; Time = day.A fixed gravity of 1.0 G, in the vertical direction downward (−z).The value of the acceleration of gravity is kept at the default value of 9.810 m/s 2 .The unit weight of the water can be defined as 10 kN/m 3 .b) Mesh and loading Mesh is divided into the full surface of the model to ensure fully every point, which is analyzed and calculated carefully to avoid errors to obtain the best results.Moreover, the changing loading is active after finishing the of process setting up the input data (see Table 3).There are two stages to active loading.The first stage is no loading, which is according to the horizontal earth coefficient K 0 = 0, which means the direct generation of initial effective stress, pore pressures, and state parameters.The equilibrium is not guaranteed.The gravity loading shows the initial stresses from the finite element calculation.It is to be used for non-horizontal layers.On the other hand, the second stage shows active loading, which means "Plastic" shows elastoplastic drained or undrained analysis and consolidation not considered; whereas "Consolidation" shows Timedependent analyses of deformation and excess pore pressures.The input of soil permeability is required.Use non-zero time intervals.Moreover, "Safety" shows the calculation of the global safety factor by means of the strength reduction method.The mesh was not further updated during a safety analysis.c) Input data and output data of the simulation Input and output data of the model simulation are set up carefully before the calculation process has begun to avoid errors and obtain the best results.

Water content (Humidity) W% with the different depths (m)
Water content (Humidity) (W%) was determined particularly at three boreholes "HK1, HK2, and HK3" with 12 samples per borehole.Groundwater levels (Depths) changed from 0.0 m to 40.0 m of the ground levels.The water content variation coefficient "ψ" show clearly according to the type of soil (Clay and Sand) at the different depths.This is an empirical coefficient.
Water content (W%) is calculated by the formula below: Whereas, the value "0.18" shows the standard humidity of 18% (see Table 5).
Experiment results have been shown particularly as water content (W%) is the maximum value of 94.35% (borehole "HK 2") at 4.8 m depth; whereas the minimum value is 18.22% at 39.3 m depth (borehole "HK3").The mean values are at the center of the layers at depths from 4.3 m to 15.3 m, and approximately 36.2%.On the contrary, the end of the layer is up to 19.95% at 18.3 m depth and up to 39.3 m depth (see Figure 2,4).
With (M.Ahmadi et al., 2021) used equations for the determination of the water content of contaminated specimens, such as:  where W 1 is wet soil weight, W 2 is dry soil weight, W 3 is specimen weight before using the oven, W 4 is specimen weight after using the oven, ω r is oil residual after evaporation of oil in the room, ω 0 is oil residual after evaporation of oil in the oven, and ω% is water content.
With (Lan et al., 2022), the natural water content (w n ,%) of the Layer 8 clay at 36.2 m depth with a maximum value of 35.6%.

Porosity (P%) with the different depths
Porosity variations were determined carefully at three boreholes, which included 12 samples per borehole.The depths changed from 0.0 m to 40.0 m ground.
Porosity is calculated by the formulas below: Whereas, the value "0.40" shows soil with a standard porosity of 40% (η can be determined in Table 3).The porosity variations coefficient "η" show clearly according to the type of soil (Clay and Sand) at the different depths.This is an empirical coefficient.
From the results in Figure 3, it is easier to see that the maximum value of the "HK2" at 4.8 m because it is located in the nearest location at the ground surface, whereas the groundwater level obtained the high value.As a result, the water content obtained has the largest value.On the other hand, it decreases suddenly at 7.5 m depth, and then becomes gradually stable as increasing of depths.The remaining values are near stability and low values, because they are located farther than the groundwater level.
With Tai and Dong (2022), researched on the porosity by supporting Clay Shell Model (CSM) for clayey sandstones, which was shown by the equation below: Whereas α ðP p ;σ c Þ is a pore pressure/confining stress dependent ("stress-dependent" thereafter) effective stress coefficient.The porosity (P) of clayey sandstone is assumed to be 0.2; For the tested Rothbach sandstones, the porosity (P) was 0.25, and the clay content was 0.04.
With Bailin (0000) also found that the effective stress coefficient α of sandstones increases with increasing porosity.
Experiment results were shown the Porosity (P%) has been obtained clearly at the maximum value of 71.9% (borehole "HK2") at 4.8 m depth; whereas the minimum value is only 40.4% (borehole "HK3") at 4.8 m depth.At the closer ground level, porosity is bigger than in locations with increasing depths (93.3 m with 40.81%).The mean values at the center of the ground obtain 48.36.Whereas the other mean values obtained 7.5 m up to 39.3 m approximately 41.26% (fewer variations); (see Figure (5,6)).

Saturation (S%) with depths (m)
Saturation (S%) and Depths (m) are determined carefully at three boreholes "HK1, HK2, and HK3" from 0.0 m to 40.m depths.The maximum saturation value is 94.26% at 4.8 m depth; the minimum value is 70.56% at 39.3 m depth.And a low mean value of 88.09% at the center of the ground.;whereas the mean value at the end layer is up to 76.23% (see Figure (7,8)).
Saturation can be calculated by the formula below: Whereas the coefficient "0.7" show soil becomes a saturation state of 70% (see Table 6).

Consideration of the relationship between water content (W%), porosity (P%), saturation (S %), and depths (m)
Variations of the water content (W%) with depths, which are related to the porosity (P%) was shown in Figure (9,10).When porosity increases evenly, at this time the pore hole in the soil is large, this results in water entering the pore hole and filling out fully of poreholes, water content increases more and more into the pore holes, so saturation increases evenly; respectively.

The internal friction angle variations with depths
The internal friction angle variations (ϕ 0 ) were determined in the Mohr-Coulomb theory, which is the same as the effective value "ϕ"' (see Table 8).
The remaining results were shown in Table 7.The mean value was obtained at 13.5032.3'as compared with the other mean value of 23.080 24.25' from 18.3 m to 39.3 m depths.And the mean value at the center of the ground was obtained at 9.580 8.08 ' (Figures (11,12)).
However, the research on the rough foundation with the bearing capacity coefficient (N γ ) of the foundations located adjacent to the slope inclination, results presented an increase in friction angle φ = 30° − 40° as the increase in value Nγ equal to 2.10 and 2.42 times the smooth foundation (S.Ahmadi et al., 2022).
Moreover, research on the effective friction angles with depths of the clay results described in formulas S u p a ¼ 1:7e À 4:6I L for the undrained tri-axial calculated the higher undrained shear strength s u = 484 kPa and higher maximum effective friction angle φ' max = 38° were measured in the Layer 8 clay at a depth of 57 m.The effective friction angles are larger than those of Layer 10, with the latter being deeper (Lan et al., 2022).
For (X. Chen et al., 2022), research on the formation of consolidated soil.Results presented the internal friction angles (φ) and a special force similar to the cohesive forces (c) of these samples were obtained in Table 6.(see Table 9).The internal friction angles (φ) of consolidated  silt increased with the depth of the soil layer.At the bottom soil layer of was greater than that of the initial seabed and loose soil sample.The larger and the stronger of the internal friction angle.This trend indicated that the particles were embedded together.Moreover, the most stable position of the particles and the selfstructures were improved, and the connection between particles became stronger during the formation of consolidated silt.The hardening forces of the particles were extended by increasing the internal friction angle of the consolidated silt.
On the other hand (Lai et al., 2022), the simulation model for an improved analytical framework to estimate active earth pressure in narrow c -ϕ soils behind rotating walls about the base.The results described the residual friction angle was a plane slip surface for higher ϕ and lower δ.And the distribution of σ w /γH along z/H with change ϕ.On the other hand, the roughness factor of the wall-soil interface (δ/ϕ) is corrected at 0.7 of the effect of soil friction angle.When the value of z/H increased then σ w /γH increased to a threshold, whereas the value of the (C2-1) ccotϕ decreased gradually (see equations 8, 9, and 10).
The active earth pressure exerted in the lower zone can be determined: Whereas C1 -C18 is abbreviations used in the derivation process; B is the width of narrow soils behind retaining wall (m); c is soil cohesion (kPa); γ is the unit weight (kPa); H is retaining wall height (m); σ lower w is active earth pressure exerted in upper and lower zones (kPa); z is a specific depth of plane slip from loading point to surface.The residual friction angle was a planar slip surface for higher ϕ and lower δ.

Results for simulation
Results from simulation of the PLAXIS 3D software for Saturation and groundwater levels variations with Depths (Brinkgreve, 2014).Results show clearly that with the maximum saturation value is 92.63% at 4.8 m depth; The minimum value is 70.44% at 39.3 m depth.Moreover, the remarkable variation is also described at 18.3 m depth with 82.65%, which decreases gradually to 70.44% at 39.3 m depth.
In addition, at the depths of 21.3 m and 33.3 m with 83.51%; 71.22%; and 70.61%; whereas a little difference compared between 24.3 m and 39.6 m depths with 82.91%; 80.12%; 70.22%; 70.12%; 71.14%; 70.44%.From the above analysis, during this stage (from 4.3 m to 15.3 m depths), saturation becomes stabilities and has a relatively low mean value of 86.79% at the center of the ground.These variations increase gradually from 18.3 m to 39.3 m depths.The mean value at the end layer is up to 75.42%.
Results from simulation by the PLAXIS 3D software for the Internal friction angle and the different groundwater levels variations with depths (z)    ) has been presented particularly with different depths, which was calculated particularly from 0.0m to 27.0m at boreholes "HK1, HK2, HK3."At borehole "HK3" shew the internal friction angle increased clearly as the depth increased gradually; whereas borehole "HK1" increased slowly and evenly.
Loose Soil (a) τ/(kPa) τ = 0.57σ + 5.2 τ = 0.56σ + 12.8 τ = 0.63σ + 20.5 τ = 0.67σ + 25.3 τ = 0.58σ + 6.9 c/(kPa) 5.2 5.2 5.2 5.2 6.9 φ/( 0    However, some researches show the difference in the friction angle.A multi-arch model to predict the limit support pressure (LSP) acting on a tunnel face was used for the deep shield tunneling in dry cohesionless soils.This research has been done by the limit equilibrium method.The numerical model included the upper end-bearing arch, the center of the friction arch, and the stability zone; whereas the lower wedge.The results show that the soil internal friction angle φ, the soil-cutter head friction angle δ, and the soil volume bulking factor α (when α > 0.04); this values significantly affected the LSP acting on the tunnel face; and the maximum values of the friction angle was changed in φ = 30°, 35°, 40°, and 45° as volume bulking "σT/(γD)" decreases remarkably (R. P. Chen et al., 2019).
Moreover, with research on the cryogenic sample data.Results show the normal stress threshold for the linear fits performed particularly in Table 10 ( Avdellidou et al., 2020).
Moreover, some research results show the lowest residual friction angle values with fine-grained sediments in Table 11 (see Table 11).And research on Numerical modelling of the growth of polygonal   Table 10.Bulk cohesion and angle of internal friction (AIF) were computed for asteroid simulant samples from shear strength measurements (Avdellidou et al., 2020).Drained ring shear Kopf et al. (1999) breaksystems to discovery the relationships between different break plane dip, residual friction of the break, and the bulk material characteristics of the sedimentary systems, which saved the polygonal break system as the maximum value of the friction angle was up to 300 on the plane dip corresponding to the highest sensitive state (King et al., 2022).With (T.Luo et al., 2022), The Hydrate forms presented an increasing friction angle as there is a transform of the pores together with marine sediments the friction angle was determined for tetrahydrofuran (THF) hydrate particles under temperature variations.Results presented that the THF hydrate is equal to hydrate deposits, whereas the larger than compared with pure methane hydrate.On the other hand, the particle diameter changes, which are created by the Hydrate micromechanical force (MMF).The test devices were done with the hydrate aggregation from 600-800 μm; which is similar to the diameter (500-1000 μm) of the large sand particles in the hydrate sediments.Moreover, with the other research, Hydrate formation from high water content-crude oil emulsions, the actual size of the hydrate particles is much smaller, of the order of tens of microns (Greaves et al., 2021).

Conclusions
Experiment measurement methods in the laboratory and simulation by the Viet Nam Standard were used to determine variations of the Water content (W%), porosity (P%), saturation (S%), and the internal friction angle at the different depths where the groundwater level is at 0.0 m.The experiment results found water content, porosity, and saturation increased gradually at the nearest ground level and decreased gradually when the depth increased gradually.Compared with the internal friction angle, values decrease gradually when depths increased gradually.On the other hand, the increase of the mean value of the internal friction angle was obtained at 13.5032.3'.As compared with the other mean value of 23.080 24.25' from 18.3 m to 39.3 m depths.The mean values at the center of the ground are small, whereas the end of the ground is big with 9.580 8.08.' The simulation method by the Plaxis 3D (finite element method) was used for the calculation and simulation of the vertical displacement variations at different depths.The results were obtained particularly for the smallest vertical displacement of the ground.The mean value at the center of the Clay layer (from 0.0 m to 27.0 m) depths was obtained at 0.0577 m, whereas was compared with 0.0156 m at the Sand layer from 27.0 m to 39.6 m depths.As a result, the ground displacement is small and not remarkable, and the ground is stabilized for building construction.Please consideration with my new manuscript as soon as possible.
Thank you very much for your help!

Figure 3 .
Figure 3. (a, b) the boundary condition and active loading; (c) mesh division of the model simulation.

Figure 4 .
Figure 4.The total water content (W%) was measured carefully at the different depths, which is shown from 0.0m to 40.0m at boreholes "HK1, HK2, HK3." values varied relatively evenly and decreased evenly as the increasing of depths".

Figure 5 .
Figure 5.The porosity (P%) has been shown clearly by the different depths, which is from 0.0m to 27.0m at borehole "HK1, HK2, and HK3."Values varied relatively unevenly and decreased evenly as the increasing of depths".

Figure 6 .
Figure 6.The total of the porosity values (P%) has been shown clearly and unevenly by the increase of the different depths, which were counted for 0.0m to 40.0m depths at boreholes "HK1, HK2, HK3;" respectively.

Figure 7 .
Figure 7.The saturation (S%) of boreholes varied remarkably and unevenly as the increasing of the different depths, which measured from 0.0m to 27.0m depths at boreholes HK1, HK2, HK3."This differences have been shown clearly decreasing of saturation as increasing of depths.

Figure 8 .
Figure 8.The total saturation values (S%)were described clearly and decreased unevenly by the different depths, which are measured particularly from 0.0m to 40.0m at three boreholes "HK1, HK2, HK3".

Figure 11 .
Figure 11.Normalized active earth pressure distribution along wall depth with the varying soil friction angle (Lai et al., 2022).

Figure 12 .
Figure12.The Internal friction angle (ϕ 0 ) has been presented particularly with different depths, which was calculated particularly from 0.0m to 27.0m at boreholes "HK1, HK2, HK3."At borehole "HK3" shew the internal friction angle increased clearly as the depth increased gradually; whereas borehole "HK1" increased slowly and evenly.

Figure 13 .
Figure13.The total of internal friction angle (ϕ 0 ) has been presented particularly with the different depths, which were collected from 0.0m to 40.0m at boreholes "HK1, HK2, HK3".

Figure 14 .
Figure14.The internal friction angle (ϕ 0 ) has been presented particularly with the relative porosity, water content, and saturation at the different depths, which was determined carefully from 0.0m to 27.0m at borehole "HK1".

Figure 15 .
Figure15.The internal friction angle (ϕ 0 ) has been presented particularly with the relative porosity, water content, and saturation at the different depths, which was determined carefully from 0.0m to 27.0m at borehole "HK2".

Figure 17 .
Figure17.The total internal friction angle (ϕ 0 ) has been presented particularly with the different depths, which were calculated carefully from 0.0m to 27.0m at boreholes "HK1, HK2, HK3." Generally, the values varied evenly with depths increasing gradually.For exception, water content values at borehole "HK2" varied remarkably.

Figure 16 .
Figure16.The internal friction angle (ϕ 0 ) has been presented particularly with the relative porosity, water content, and saturation at the different depths, which was determined carefully from 0.0m to 27.0m at borehole "HK3".

Figure 18 .
Figure18.The total of the internal friction angle (ϕ 0 ) has been presented particularly with the different depths, which were determined particularly from 0.0m to 40.0m at boreholes "HK1, HK2, HK3".

Figure 20 .
Figure 20.The saturation (S%) is related to the decreasing of the matric suction (kPa), which has been shown at the clay layer of the boreholes "HK1, HK2, and HK3."The saturation curve decreased gradually as matric suction increased gradually.

Figure 19 .
Figure 19.The family of SWCCs was developed by zapatata in 1999.

Figure 21 .
Figure21.The saturation (S%) related to the decreasing of the matric suction (kPa), which has been shown at the sand layer of the boreholes "HK1, HK2, and HK3."The saturation curve decreased strongly at borehole "HK1;" whereas compared with relative decrease at borehole "HK3."In contrast, at borehole "HK3" increased gradually.

Figure 22 .
Figure 22. (From (a) to (m)).The results of the saturation and groundwater level variations with depths, which is shown by simulation of the PLAXIS 3D software.The saturation decreased the depth increased remarkably.

Figure 23 .
Figure 23.The results of the internal friction angle and the different groundwater level variations with the different depths (z), which was shown by the simulation of the PLAXIS 3D software.The depths increased gradually as the internal friction angle increased remarkably.

Figure 24 .
Figure 24.Comparison of friction angles of hydrate-bearing sediment and pure hydrate under different measured conditions (Luo.T et al, 2022).

Table 4 .
Input and output data of the model simulation and Results