1/ Factors affect the soil permeability? (by Vinh) 1. GRAIN SIZE: The Permeability varies approximately as the square of grain size It depends on the effective diameter of the grain size (D10) . K=C (D10)2 K is Permeability in cm/sec . C is constant and generally lies between 100 to 150. 2. PROPERTIES OF PORE FLUID: Pore fluids are fluids that occupy pore spaces in a soil or rock. Permeability is directly proportional to the unit weight of pore fluid and inversely proportional to viscosity of pore fluid. 3. TEMPERATURE : As the viscosity of the pore fluid decrease with the temperature , permeability increases with temperature , as unit weight of pore fluid does not change much with change in temperature. 4. VOID RATIO: Increase in the void ratio increases the area available for flow hence permeability increases for critical conditions. 5. STRATIFICATION OF SOIL: Stratified soils are those soils which are formed by layer upon layer of the earth or dust deposited on each other. If the flow is parallel to the layers of stratification , the permeability is max. while the flow in Perpendicular direction occur with min. permeability. 6.ENTRAPPED AIR AND ORGANIC IMPURITIES: The organic impurities and entrapped air obstruct the flow and coefficient of permeability is reduce due to their presece. 7. ADSORBED WATER: Adsorbed Water means a thin microscopic film of water surrounding individual soil grains This water is not free to move and hence reduces the effective pore space an thus decreases coefficient of permeability . 8. DEGREE OF SATURATION: The permeability of partially saturated soil is less than that of fully saturated soil. 9. SHAPE OF PARTICLES: Permeability is inversely proportional to specific surface e.g. as angular soil have more specific surface area compared to the round soil therefore, the soil with angular particles is less permeable than soil of rounded particles. 10. STRUCTURE OF SOIL MASS: For same void ratio the permeability is more for flocculent structure as compared to the dispended structure. 2/Set up the Terzaghi equation for consoliation? (By Nam) During the consolidation process, when the effective stress increased from initial σo the current σ’, water is squeezed out at the amount of Δn, and the current volume of void becomes n as seen. Thus, mv is defined as the coefficient of volume change so . where u is pressure in pore water according to Darcy law: i: hydraulic gradient (head loss/flow length = Δh/L) ∂hp is the pressure head difference and is negative for positive water flow velocity v in Figure 9.4. From Equation (9.9), where: assume that: FIGURE 9.5 Initial and boundary conditions for the consolidation equation. Fourier analysis: To simplify the expression, we set up: Then: By referring to the three-phase diagram of Figure 9.3 and using Equation (9.2), the final consolidation settlement Sf (at t = ∞) for a clay layer of thickness H can be obtained as: where Δσ is the increased stress at depth z. Since u is given in Equation (9.16), Equation (9.18) becomes Now, the degree of consolidation U is defined as the percentage of settlement at an arbitrary time t to its final settlement at t = ∞ and it is computed from Equations (9.17) and (9.19) as 3/ Show the asumptions and Terzaghi'' model for consolidation? (by Hoàng) Assumptions of Terzaghi''s Principle : The soil is homogenous (uniform in composition throughout). The soil is fully saturated (zero air voids due to water content being so high). The solid particles and water are incompressible. Compression and flow are one-dimensional (vertical axis being the one of interest). Strains in the soil are relatively small. Darcy''s Law is valid for all hydraulic gradients. The coefficient of permeability and the coefficient of volume compressibility remain constant throughout the process. There is a unique relationship, independent of time, between the void ratio and effective stress. Terzaghi''s model for consolidation: Solutions to the one-dimensional consolidation equation can be obtained by plotting the variation of with the depth in the layer at given elapsed times. The resulting curves are called isochrones. The figure shows a set of supposed standpipes inserted into a consolidating layer. Before loading, the pore pressure in the drain is zero. At the base of each standpipe there is some initial pore pressure u= uo, the excess pore pressure = 0. Immediately after the loading is applied the standpipes will each show an initial excess pore pressure of i, thereafter the excess pore pressure will dissipate. 4/ Compare the e-p and e-logp chart? (by Thái) The e-p chart: The e-logp chart: The e-p chart The e-logp chart Similarity They can help us calculate and predict the settlement from load level h1 h2 Difference It doesn’t perform the relation between void ratio (e) and the pressure (p) at small loads. Characteristic of the chart is the compressibility factor ; the more this fator is, the weaker soil is and the more soil settles. We can calculate the settlement of soil thanks to the rario e or a above Performs apparently the relation between void ratio (e) and the pressure (p) at small loads. Characteristic of the chart is the pre-consolidated pressure value pc which reflects supporting- power history of the ground base. We can calculate the settlement of soil thanks to the settlement index Cc and expand index Cs 5/ Compute the settlement formulation? And the steps to calculate settlement of foundation? (by Tuấn) _ Consider a soil sample compressed without extending horizontally. + Intially, the sample has the height h1, the cross-section area A1, the volume V1, void ratio e1 + After the compression, h2, A2, V2, e2. _ A1 = A2, S = h1 – h2 , _ Relative deformation of the soil sample _ With small force, we can consider that the volume of the particles is constant, Vs = constant _ Before the compression: _ After the compression: _ The volume Vs is constant: , V = A.h => h2 = . h1 S = h1 – h2 = h1 - . h1 => S = ∑ ∑ The steps to calculate settlement of foundation? _ Consider a foundation in the following figure: - Pressure of the soil at the bottom of the foundation. f tb tc f tb tc tc D F N F F D N F N p - Settling stress (caused by load Ntc ) at the foundation bottom. f tb tc f D F N D p ) ( With Ntc : standard load affecting on the foundation F = l x b : the area of the foundation bottom Df : depth of the foundation bottom tb : average unit weight of concrete and soil above the foundation bottom, 20 – 22 kN/m3 . : unit weight of soil above the foundation bottom. _ The steps to calculate settlement of foundation: + Step 1: Draw the settling stress ’ gl chart and vertically effective stress bt chart ’bt = γ ‘.z gl = ko pgl + Step 2: Determine the thickness of the soil which needs calculating the settlement hn, hn is the distance from the Ntc Df tb p hn b l foundation bottom to the depth where: ’bt ≥ 5 gl, good soil ’bt ≥ 10 gl, soft soil + Step 3: Divide hn into numerous small layers hi = 0,4b, at the depth away from the foundation bottom, we can choose hi = 0,4b-0,6b. And every layer must stay in only one type of soil. + Step 4: Determine the average settling stress of each layer. Effective stress caused by the soil weight at the middle of a layer is: Pli = ’bt + Step 5: The settling stress is the sum of the effective stress caused by the soil weight and settling stress at the middle of the layer. P2i = p1i +Δp = p1i + gli According to the relationship between e and p, determine: p1i e1i Consolidation test p2i e2i + Step 6: Determine the stable settlement of each layer . Then we can calculate the overall stable settlement of the foundation by use the following formula: S =∑ ∑ .hi 6/ How to calculate settlement after 6 months? And vice versus? (by Thanh) To calculate Settlement after 6 months: 1. Determine primary settlement: SC 2. Calculate coefficient of consolidation Cv be the following equation: 3. Calculate a dimensionless time factor associated with the time it takes for primary settlement to be completed TV: (with t= 6 months) the consolidating layer is drained on one side (top or bottom) ( ) the consolidating layer is drained on both sides (top and bottom) 4. Calculate U(%): ( ) for U60% 5. Calculate ST: To calculate settlement time: 1. Determine primary settlement: SC 2. Calculate coefficient of consolidation Cv be the following equation: 3. Calculate the percent of primary consolidation: 4. Calculate Tv by the following two equations: ( ) for U60% 5. Calculate settlement time: the consolidating layer is drained on one side (top or bottom) ( ) the consolidating layer is drained on both sides (top and bottom) 7/ Compare soil strength of sand and clay? (by Phúc) The shear strength and deformation behavior of sand is more straightforward than that of clay. Shear strength measurements on sand are usually carried out as drained tests since water can flow through sand very quickly, and pore pressures are not likely to be any different in the center of the sample than the values at the ends where drainage is permitted. Plot the normal stress vs. shear stress values 8/ How to determine the plastic point in sand and clay? (by Đạt) Step 1: Get the part of odd soil in the experiment to determine liquid limit, dry to near the plastic limit, hand doesn’t stick when hold but the flexibility still exists. Step 2: Use 4 fingertips to roll soil on the lustreless glass plate until the soil thread have diameter to be near 3mm, cracks appear and the distance between cracks is about 10mm. * With this diameter, if the soil stick still is not cracked, roll it into balls and roll continuosly until obtain the above result. *When the cracks appear, if D>3mm, we will add more water and roll again. Get the soil thread , which obtain the above condition, to determine the wetness. This wetness is the plastic limit. 9/Set up the equation for soil bearing capacity according to Terzaghi? (by Hòa) For determining bearing capacity for the general shear failure case For square foundations: For continuous foundations: For circular foundations: where for φ'' = 0 for φ'' > 0 c′ is the effective cohesion. σzD′ is the vertical effective stress at the depth the foundation is laid. γ′ is the effective unit weight when saturated or the total unit weight when not fully saturated. B is the width or the diameter of the foundation. φ′ is the effective internal angle of friction. Kpγ is obtained graphically. Simplifications have been made to eliminate the need for Kpγ. One such was done by Coduto, given below, and it is accurate to within 10% For foundations that exhibit the local shear failure mode in soils For square foundations: For continuous foundations: For circular foundations: , the modified bearing capacity factors, can be calculated by using the bearing capacity factors equations(for ,respectively) by replacing the effective internal angle of frictionby a value equal to 10/ How to increase soil bearing capacity? (by Trí ca =]]]) 1. Increasing depth of foundation At deeper depths, the over burden pressure on soil is higher; hence the soil is more compacted at deeper depth. As a result it shows higher bearing capacity. This is applicable only for cohesionless soils such as sandy and gravelly soils. This method of improving bearing capacity of soil is not applicable if the subsoil material grows wetter as depth increase. This method has a limited use because with increase in depth, the weight and cost of foundation also increases. 2. Draining the soil With increase in percentage of water content in soil, the bearing capacity decreases. In case of sandy soil, the bearing capacity may reduce as much as 50% due to presence of water content. Cohesionless soils (i.e. sandy & gravelly soils) can be drained by laying the porous pipes to a gentle slope, over a bed of sand and filling the trenches above the pipes with loose boulders. These trenches subsequently should lead to the nearest well or any water body. 3. Compacting the soil If we compact soil using appropriate method, then there will be increase in its density and shear strength. As a result the bearing capacity of soil also increases. There are many methods of compacting soils on site. Few of them are mentioned below. By spreading broken stones, gravel or sand and thereafter ramming well in the bed of trenches. Using an appropriate roller as per the soil type to move at a specified speed. Br driving concrete piles or wood piles and withdrawing piles and subsequently filling the holes with sand or concrete. 4. Confining the soil In this method, the soils are enclosed with the help of sheet piles. This confined soil is further compacted to get more strength. This method is applicable for shallow foundations. 5. Replacing the poor soil In this method the poor soil is first removed and then the gap is filled up by superior material such as sand, stone, gravel or any other hard material. In order to do this, first excavate a foundation trench of about 1.5 m deep, and then fill the hard material is stages of 30 cm. Then compact the hard material at every stage. This method is useful for foundations in black cotton soils. 6. Using grouting material This method is applicable for soils where there is presence of pores, fissures or cracks etc underneath the foundation. In this method, poor soil bearing strata is hardened by injecting the cement grout under pressure, because it scales off any cracks or pores or fissures etc. For proper distribution of the cement grout, the ground is bored and perforated pipes are introduced to force the grout. 7. Stabilizing the soil with chemicals This method of improving bearing capacity of soil is costly and applied in exceptional cases. In this method, chemical solutions, like silicates of soda and calcium chloride is injected with pressure into the soil. These chemical along with the soil particles form a gel like structure and develop a compact mass.This is called chemical stabilization of soil and used to give additional strength to soft soils at deeper depths. (By Tâm) 1/ The pile-pile interaction in sand significantly increases bearing capacity of the pile in a group. 2/ The raft has significant influence on mode of deformation of the base. The large volume of the soil take part in the work and increase bearing capacity of the base about 10–100 % depending on size and shape of foundation and ground conditions of the site. The large reserve of bearing capacity of the base has not investigated sufficiently. 3/ Application of short vibrostamped tapered piles with widening at the pile foots and bearing rafts is more effective than conventional foundations consist of driven prismatic piles. Compressing stress transmits into ground along the whole length of lateral pile faces without negative friction and by the raft. Upper layers of filled-up soil are compacted by means of sloping lateral pile faces and bearing capacity of this soil increasing considerably. 4/ Methods: - Lime stabilization. - Dynamic deep compaction. - Vibroreplacement. - Vibrocompaction 5/ Repalce the existing soil with road base materials and compact in layers to attain the required bearing capacity of soil. 6/ Replace the existing soil with cement mix soil and compact in layers with water to attain the required bearing capacity.
1/ Factors affect the soil permeability? (by Vinh) GRAIN SIZE: The Permeability varies approximately as the square of grain size It depends on the effective diameter of the grain size (D10) K=C (D10)2 K is Permeability in cm/sec C is constant and generally lies between 100 to 150 PROPERTIES OF PORE FLUID: Pore fluids are fluids that occupy pore spaces in a soil or rock Permeability is directly proportional to the unit weight of pore fluid and inversely proportional to viscosity of pore fluid TEMPERATURE : As the viscosity of the pore fluid decrease with the temperature , permeability increases with temperature , as unit weight of pore fluid does not change much with change in temperature VOID RATIO: Increase in the void ratio increases the area available for flow hence permeability increases for critical conditions STRATIFICATION OF SOIL: Stratified soils are those soils which are formed by layer upon layer of the earth or dust deposited on each other If the flow is parallel to the layers of stratification , the permeability is max while the flow in Perpendicular direction occur with permeability 6.ENTRAPPED AIR AND ORGANIC IMPURITIES: The organic impurities and entrapped air obstruct the flow and coefficient of permeability is reduce due to their presece ADSORBED WATER: Adsorbed Water means a thin microscopic film of water surrounding individual soil grains This water is not free to move and hence reduces the effective pore space an thus decreases coefficient of permeability DEGREE OF SATURATION: The permeability of partially saturated soil is less than that of fully saturated soil SHAPE OF PARTICLES: Permeability is inversely proportional to specific surface e.g as angular soil have more specific surface area compared to the round soil therefore, the soil with angular particles is less permeable than soil of rounded particles 10 STRUCTURE OF SOIL MASS: For same void ratio the permeability is more for flocculent structure as compared to the dispended structure 2/Set up the Terzaghi equation for consoliation? (By Nam) During the consolidation process, when the effective stress increased from initial σ o the current σ’, water is squeezed out at the amount of Δn, and the current volume of void becomes n as seen Thus, mv is defined as the coefficient of volume change so where u is pressure in pore water according to Darcy law: i: hydraulic gradient (head loss/flow length = Δh/L) ∂hp is the pressure head difference and is negative for positive water flow velocity v in Figure 9.4 From Equation (9.9), where: assume that: FIGURE 9.5 Initial and boundary conditions for the consolidation equation Fourier analysis: To simplify the expression, we set up: Then: By referring to the three-phase diagram of Figure 9.3 and using Equation (9.2), the final consolidation settlement S f (at t = ∞) for a clay layer of thickness H can be obtained as: where Δσ is the increased stress at depth z Since u is given in Equation (9.16), Equation (9.18) becomes Now, the degree of consolidation U is defined as the percentage of settlement at an arbitrary time t to its final settlement at t = ∞ and it is computed from Equations (9.17) and (9.19) as 3/ Show the asumptions and Terzaghi' model for consolidation? (by Hoàng) Assumptions of Terzaghi's Principle : The soil is homogenous (uniform in composition throughout) The soil is fully saturated (zero air voids due to water content being so high) The solid particles and water are incompressible Compression and flow are one-dimensional (vertical axis being the one of interest) Strains in the soil are relatively small Darcy's Law is valid for all hydraulic gradients The coefficient of permeability and the coefficient of volume compressibility remain constant throughout the process There is a unique relationship, independent of time, between the void ratio and effective stress Terzaghi's model for consolidation: Solutions to the one-dimensional consolidation equation can be obtained by plotting the variation of with the depth in the layer at given elapsed times The resulting curves are called isochrones The figure shows a set of supposed standpipes inserted into a consolidating layer Before loading, the pore pressure in the drain is zero At the base of each standpipe there is some initial pore pressure u= uo, the excess pore pressure = Immediately after the loading is applied the standpipes will each show an initial excess pore pressure of i, thereafter the excess pore pressure will dissipate 4/ Compare the e-p and e-logp chart? (by Thái) The e-p chart: The e-logp chart: Similarity The e-p chart The e-logp chart They can help us calculate and predict the settlement from load level Difference It doesn’t perform the relation between void ratio (e) and the pressure (p) at small loads Characteristic of the chart is the compressibility factor ; the more this fator is, the weaker soil is and the more soil settles We can calculate the settlement of soil thanks to the rario e or a above Performs apparently the relation between void ratio (e) and the pressure (p) at small loads Characteristic of the chart is the pre-consolidated pressure value pc which reflects supportingpower history of the ground base We can calculate the settlement of soil thanks to the settlement index Cc and expand index Cs 5/ Compute the settlement formulation? And the steps to calculate settlement of foundation? (by Tuấn) h1 h2 _ Consider a soil sample compressed without extending horizontally + Intially, the sample has the height h1, the cross-section area A1, the volume V1, void ratio e1 + After the compression, h2, A2, V2, e2 _ A1 = A2, S = h1 – h2 , _ Relative deformation of the soil sample _ With small force, we can consider that the volume of the particles is constant, Vs = constant _ Before the compression: _ After the compression: _ The volume Vs is constant: , V = A.h h1 => h2 = S = h1 – h2 = h1 - h1 => S = ∑ ∑ The steps to calculate settlement of foundation? _ Consider a foundation in the following figure: Ntc tb Df p hn b l - Pressure of the soil at the bottom of the foundation N p F tc N tc tb D f F F N tc tb D f F - Settling stress (caused by load Ntc) at the foundation bottom N tc p Df ( tb ) D f F With Ntc : standard load affecting on the foundation F = l x b : the area of the foundation bottom Df : depth of the foundation bottom tb : average unit weight of concrete and soil above the foundation bottom, 20 – 22 kN/m3 : unit weight of soil above the foundation bottom _ The steps to calculate settlement of foundation: + Step 1: Draw the settling stress ’ gl ’bt = γ ‘.z chart and vertically effective stress gl bt chart = ko pgl + Step 2: Determine the thickness of the soil which needs calculating the settlement h n, hn is the distance from the foundation bottom to the depth where: ’bt ≥ gl, ’bt ≥ 10 good soil gl, soft soil + Step 3: Divide hn into numerous small layers hi = 0,4b, at the depth away from the foundation bottom, we can choose hi = 0,4b-0,6b And every layer must stay in only one type of soil + Step 4: Determine the average settling stress of each layer Effective stress caused by the soil weight at the middle of a layer is: Pli = ’bt + Step 5: The settling stress is the sum of the effective stress caused by the soil weight and settling stress at the middle of the layer P2i = p1i +Δp = p1i + gli According to the relationship between e and p, determine: p1i e1i Consolidation test p2i e2i + Step 6: Determine the stable settlement of each layer Then we can calculate the overall stable settlement of the foundation by use the following formula: S =∑ ∑ hi 6/ How to calculate settlement after months? And vice versus? (by Thanh) To calculate Settlement after months: Determine primary settlement: SC Calculate coefficient of consolidation Cv be the following equation: Calculate a dimensionless time factor associated with the time it takes for primary settlement to be completed TV: (with t= months) the consolidating layer is drained on one side (top or bottom) ( ) the consolidating layer is drained on both sides (top and bottom) Calculate U(%): ( ) for U60% Calculate ST: To calculate settlement time: Determine primary settlement: SC Calculate coefficient of consolidation Cv be the following equation: Calculate the percent of primary consolidation: Calculate Tv by the following two equations: ( ) for U60% Calculate settlement time: the consolidating layer is drained on one side (top or bottom) ( ) the consolidating layer is drained on both sides (top and bottom) 7/ Compare soil strength of sand and clay? (by Phúc) The shear strength and deformation behavior of sand is more straightforward than that of clay Shear strength measurements on sand are usually carried out as drained tests since water can flow through sand very quickly, and pore pressures are not likely to be any different in the center of the sample than the values at the ends where drainage is permitted Plot the normal stress vs shear stress values 8/ How to determine the plastic point in sand and clay? (by Đạt) Step 1: Get the part of odd soil in the experiment to determine liquid limit, dry to near the plastic limit, hand doesn’t stick when hold but the flexibility still exists Step 2: Use fingertips to roll soil on the lustreless glass plate until the soil thread have diameter to be near 3mm, cracks appear and the distance between cracks is about 10mm * With this diameter, if the soil stick still is not cracked, roll it into balls and roll continuosly until obtain the above result *When the cracks appear, if D>3mm, we will add more water and roll again Get the soil thread , which obtain the above condition, to determine the wetness This wetness is the plastic limit 9/Set up the equation for soil bearing capacity according to Terzaghi? (by Hòa) For determining bearing capacity for the general shear failure case For square foundations: For continuous foundations: For circular foundations: where for φ' = for φ' > c′ is the effective cohesion σzD′ is the vertical effective stress at the depth the foundation is laid γ′ is the effective unit weight when saturated or the total unit weight when not fully saturated B is the width or the diameter of the foundation φ′ is the effective internal angle of friction Kpγ is obtained graphically Simplifications have been made to eliminate the need for Kpγ One such was done by Coduto, given below, and it is accurate to within 10% For foundations that exhibit the local shear failure mode in soils For square foundations: For continuous foundations: For circular foundations: equations(for equal to , the modified bearing capacity factors, can be calculated by using the bearing capacity factors ,respectively) by replacing the effective internal angle of frictionby a value 10/ How to increase soil bearing capacity? (by Trí ca =]]]) Increasing depth of foundation At deeper depths, the over burden pressure on soil is higher; hence the soil is more compacted at deeper depth As a result it shows higher bearing capacity This is applicable only for cohesionless soils such as sandy and gravelly soils This method of improving bearing capacity of soil is not applicable if the subsoil material grows wetter as depth increase This method has a limited use because with increase in depth, the weight and cost of foundation also increases Draining the soil With increase in percentage of water content in soil, the bearing capacity decreases In case of sandy soil, the bearing capacity may reduce as much as 50% due to presence of water content Cohesionless soils (i.e sandy & gravelly soils) can be drained by laying the porous pipes to a gentle slope, over a bed of sand and filling the trenches above the pipes with loose boulders These trenches subsequently should lead to the nearest well or any water body Compacting the soil If we compact soil using appropriate method, then there will be increase in its density and shear strength As a result the bearing capacity of soil also increases There are many methods of compacting soils on site Few of them are mentioned below By spreading broken stones, gravel or sand and thereafter ramming well in the bed of trenches Using an appropriate roller as per the soil type to move at a specified speed Br driving concrete piles or wood piles and withdrawing piles and subsequently filling the holes with sand or concrete Confining the soil In this method, the soils are enclosed with the help of sheet piles This confined soil is further compacted to get more strength This method is applicable for shallow foundations Replacing the poor soil In this method the poor soil is first removed and then the gap is filled up by superior material such as sand, stone, gravel or any other hard material In order to this, first excavate a foundation trench of about 1.5 m deep, and then fill the hard material is stages of 30 cm Then compact the hard material at every stage This method is useful for foundations in black cotton soils Using grouting material This method is applicable for soils where there is presence of pores, fissures or cracks etc underneath the foundation In this method, poor soil bearing strata is hardened by injecting the cement grout under pressure, because it scales off any cracks or pores or fissures etc For proper distribution of the cement grout, the ground is bored and perforated pipes are introduced to force the grout Stabilizing the soil with chemicals This method of improving bearing capacity of soil is costly and applied in exceptional cases In this method, chemical solutions, like silicates of soda and calcium chloride is injected with pressure into the soil These chemical along with the soil particles form a gel like structure and develop a compact mass.This is called chemical stabilization of soil and used to give additional strength to soft soils at deeper depths (By Tâm) 1/ The pile-pile interaction in sand significantly increases bearing capacity of the pile in a group 2/ The raft has significant influence on mode of deformation of the base The large volume of the soil take part in the work and increase bearing capacity of the base about 10–100 % depending on size and shape of foundation and ground conditions of the site The large reserve of bearing capacity of the base has not investigated sufficiently 3/ Application of short vibrostamped tapered piles with widening at the pile foots and bearing rafts is more effective than conventional foundations consist of driven prismatic piles Compressing stress transmits into ground along the whole length of lateral pile faces without negative friction and by the raft Upper layers of filled-up soil are compacted by means of sloping lateral pile faces and bearing capacity of this soil increasing considerably 4/ Methods: Lime stabilization - Dynamic deep compaction - Vibroreplacement - Vibrocompaction 5/ Repalce the existing soil with road base materials and compact in layers to attain the required bearing capacity of soil 6/ Replace the existing soil with cement mix soil and compact in layers with water to attain the required bearing capacity ... following formula: S =∑ ∑ hi 6/ How to calculate settlement after months? And vice versus? (by Thanh) To calculate Settlement after months: Determine primary settlement: SC Calculate coefficient