www.sefindia.org

[Bubalan]

Sir,We have done stone column for one of our projects and it's good alternative for lightly loaded structure

regards
Bubalan Sundaram



On Mon, 4 Sep, 2023, 4:26 pm glnp12, <forum@sefindia.org (forum@sefindia.org)> wrote:

[PRAMODPS01]

Calculating the bearing capacity of soil after stone piling involves several steps. To increase the bearing capacity from 3.3t/sqm to 7.0t/sqm, you'll likely need to perform the following:

1. Soil Investigation: Conduct a detailed soil investigation to understand the soil properties, depth of weak layers, and the extent of stone piling needed. Soil samples should be collected and analyzed in a laboratory to determine their properties.


2. Design Stone Piles: Determine the size, spacing, and depth of stone piles needed to improve the bearing capacity. The design depends on the soil properties and the target bearing capacity.


3. Installation of Stone Piles: Install the stone piles at the specified locations and depths. Common methods include vibro-replacement or driven stone columns.


4. Load Testing: Conduct load tests to verify the actual improvement in bearing capacity achieved with the stone piles. This will help ensure that the desired bearing capacity of 7.0t/sqm is met.


5. Calculations: Calculate the bearing capacity after stone piling using the appropriate engineering formulas. One common method is using Terzaghi's bearing capacity equation:


   [q = c'Nc + γDfNq + 0.5γBNγ]


   - (q) = Ultimate bearing capacity after stone piling (7.0t/sqm)
   - (c') = Effective cohesion of soil after stone piling
   - (Nc), (Nq), and (Nγ) = Bearing capacity factors
   - (γ) = Unit weight of soil
   - (Df) = Depth of influence of stone piling
   - (B) = Width of the foundation


6. Determine Effective Cohesion: Calculate the effective cohesion of the soil after stone piling. This can be based on the laboratory tests and the properties of the stone material used.


7. Depth of Influence: Calculate the depth of influence of the stone piling. It is usually determined based on the size and spacing of the stone piles.


8. Foundation Design: Design the foundation based on the calculated bearing capacity to ensure it can safely support the intended loads.


9. Monitoring: Monitor the performance of the foundation over time to ensure it continues to meet the desired bearing capacity.



Pramod P S



On Fri, 1 Sep 2023, 9:18 pm rayeesnaqashbandi, <forum@sefindia.org (forum@sefindia.org)> wrote:

[anandanv]

Please go for drop weight test.

On Fri, Sep 1, 2023 at 10:26 PM rayeesnaqashbandi <forum@sefindia.org (forum@sefindia.org)> wrote:

[venkatarangarao]

Pl use IS 15284-1 for design of SBC using stone columns.This is self explanatory Thanks & regards
Rangarao V V
Ph.D (Strl Engg) - IIT- Hyderabad


SL Structural Consortium, Eco friendly innovation is the way...
741, Naveen Nagar Colony, Flat No. 7, Banjara Anand Apts,
Hyderabad- 500 004 Tel : 040 66669766 
www.slstructural.com





















On Fri, Sep 1, 2023 at 11:59 PM rayeesnaqashbandi <forum@sefindia.org (forum@sefindia.org)> wrote:

[Arunachalam]

Dear Sir
the method of stone piling is not the proper design in view of the surrounding soil is marsh, loose filled, riverside sand dunes and with raised water 
table.  While vibrated compaction what is the quantity of  and size of stone and in between filler materials used. As per the above method of stone/sand  piling building columns sunk 4'' and the floor above curtailed and the interesting decision to improve the SBC was given by IIT , Chennai. 
Note: Vibarated compaction is not properly done  was the decision given by the IIT , after the column sunk, but the IIT did not quantify the Equipment used, duration, and after the work done, method of test also not done above the layer. 


In such cases identify the hard layer  and decide the type of foundation is the option depend on loads, type and importance of structure etc


With regardsS.Arunachalam

9486100753/9442400753(whatsapp)










On Thu, Sep 7, 2023 at 10:05 PM PRAMODPS01 <forum@sefindia.org (forum@sefindia.org)> wrote:

[quote]            Calculating the bearing capacity of soil after stone piling involves several steps. To increase the bearing capacity from 3.3t/sqm to 7.0t/sqm, you'll likely need to perform the following:

1. Soil Investigation: Conduct a detailed soil investigation to understand the soil properties, depth of weak layers, and the extent of stone piling needed. Soil samples should be collected and analyzed in a laboratory to determine their properties.


2. Design Stone Piles: Determine the size, spacing, and depth of stone piles needed to improve the bearing capacity. The design depends on the soil properties and the target bearing capacity.


3. Installation of Stone Piles: Install the stone piles at the specified locations and depths. Common methods include vibro-replacement or driven stone columns.


4. Load Testing: Conduct load tests to verify the actual improvement in bearing capacity achieved with the stone piles. This will help ensure that the desired bearing capacity of 7.0t/sqm is met.


5. Calculations: Calculate the bearing capacity after stone piling using the appropriate engineering formulas. One common method is using Terzaghi's bearing capacity equation:


   [q = c'Nc + ÃŽ³DfNq + 0.5ÃŽ³BNÃŽ³]


   - (q) = Ultimate bearing capacity after stone piling (7.0t/sqm)
   - (c') = Effective cohesion of soil after stone piling
   - (Nc), (Nq), and (NÃŽ³) = Bearing capacity factors
   - (ÃŽ³) = Unit weight of soil
   - (Df) = Depth of influence of stone piling
   - (B) = Width of the foundation


6. Determine Effective Cohesion: Calculate the effective cohesion of the soil after stone piling. This can be based on the laboratory tests and the properties of the stone material used.


7. Depth of Influence: Calculate the depth of influence of the stone piling. It is usually determined based on the size and spacing of the stone piles.


8. Foundation Design: Design the foundation based on the calculated bearing capacity to ensure it can safely support the intended loads.


9. Monitoring: Monitor the performance of the foundation over time to ensure it continues to meet the desired bearing capacity.



Pramod P S



On Fri, 1 Sep 2023, 9:18 pm rayeesnaqashbandi, forum@sefindia.org (forum@sefindia.org))> wrote:

      --auto removed--

Posted via Email

[saripalli]

I don't know if this message finds a place. Because the website doesn't find my email and password. 1.In 1987 some one did stone column for the hotten spears for BPCL plant at URAN near panvel( New Mumbai).
2.One hottest spears foundation has yield before loading the gas.
3.Most places drainage column have worked. Like in Visakhapatnam in 1995-96.
But.
Finding the N=100 is many times a blame game.
Regards
S.Suryanarayana. BE.,FIV Sr.P.E ( ECI).Fellow IIBE and ACCE

Sent from Yahoo Mail on Android

[Sanjay Jain]

 Dear sir and friends
We have the problem at site


The current practical problem for the foundation of the building is that the site has yellow soil with a small amount of kankar available at a depth of more than 10 meters. Additionally, the entire area is prone to flooding during the rainy season, as it is situated near the Kaliyasot River.


The proposed building is a five-story parking structure with the plinth level set 6 feet above the approach road. Below the parking floor level, plans include water storage tanks, a fire water storage tank, and a septic tank.


For the foundation at the site, we plan to use 400 mm diameter piles, extending to a depth of 6 meters, and filled with GSB material, arranged in a grid with a spacing of 1.2 meters center to center. The outer perimeter piles, which are unreinforced, are also 400 mm in diameter, placed in two rows with a spacing of 1.5 meters center to center. These outer piles are filled with reinforced cement concrete.


To support the outer unreinforced piles, there will be a strip footing raft with a thickness of 600 mm and a width of 1.8 meters. The inner portion of the site, where stone-filled piles are used, will have GSB material layered above them. Across the entire area, a 500 mm thick raft will be constructed to support the columns.
The SBC of soil 6t/sqmt .
The average load   on column to 250 t.


This design is a practical solution considering the challenging soil conditions and the potential for flooding near the river. It provides a stable foundation for the proposed building.


Please suggest me
The right approach
If any
Sanjay Jain M.tech 
Structural designer 
Vardhman associates
Bhopal
9826032331


On Fri, 8 Sept 2023, 9:17 am PRAMODPS01, <forum@sefindia.org (forum@sefindia.org)> wrote:

[quote]            Calculating the bearing capacity of soil after stone piling involves several steps. To increase the bearing capacity from 3.3t/sqm to 7.0t/sqm, you'll likely need to perform the following:

1. Soil Investigation: Conduct a detailed soil investigation to understand the soil properties, depth of weak layers, and the extent of stone piling needed. Soil samples should be collected and analyzed in a laboratory to determine their properties.


2. Design Stone Piles: Determine the size, spacing, and depth of stone piles needed to improve the bearing capacity. The design depends on the soil properties and the target bearing capacity.


3. Installation of Stone Piles: Install the stone piles at the specified locations and depths. Common methods include vibro-replacement or driven stone columns.


4. Load Testing: Conduct load tests to verify the actual improvement in bearing capacity achieved with the stone piles. This will help ensure that the desired bearing capacity of 7.0t/sqm is met.


5. Calculations: Calculate the bearing capacity after stone piling using the appropriate engineering formulas. One common method is using Terzaghi's bearing capacity equation:


   [q = c'Nc + ÃŽ³DfNq + 0.5ÃŽ³BNÃŽ³]


   - (q) = Ultimate bearing capacity after stone piling (7.0t/sqm)
   - (c') = Effective cohesion of soil after stone piling
   - (Nc), (Nq), and (NÃŽ³) = Bearing capacity factors
   - (ÃŽ³) = Unit weight of soil
   - (Df) = Depth of influence of stone piling
   - (B) = Width of the foundation


6. Determine Effective Cohesion: Calculate the effective cohesion of the soil after stone piling. This can be based on the laboratory tests and the properties of the stone material used.


7. Depth of Influence: Calculate the depth of influence of the stone piling. It is usually determined based on the size and spacing of the stone piles.


8. Foundation Design: Design the foundation based on the calculated bearing capacity to ensure it can safely support the intended loads.


9. Monitoring: Monitor the performance of the foundation over time to ensure it continues to meet the desired bearing capacity.



Pramod P S



On Fri, 1 Sep 2023, 9:18 pm rayeesnaqashbandi, forum@sefindia.org (forum@sefindia.org))> wrote:

      --auto removed--

Posted via Email

[ramesh1910]

Dear Team and Mr. Rayees,

My experience is as follows.

1. In "Rann of Kutchch, Gujarat", India; we were working for Wind Power plant. The nature of soil was Liquifiable soil (Loose sand) with bearing capacity of around 1Ton/sq.m.

2. The required bearing capacity is 26 Ton/sq.m

3. We have designed (soil improvement) with "Stone Columns".
     The diameter of stone colum      = 700 mm
     Spacing of stone columns           = 2100 mm c/c in
     Patternn of arrangement          = triangular pattern
     Depth of stone column          = 12000 mm below Foundation
     Aggregate                         = 50 mm down size
     Method of stone column          = Displacement method (i.e., Vibro type)
     And, 500mm thick stone blanket below foundation for drainage of excess pore water pressure which comes out through stone column

4. After the installation of stone columns, we have conducted the plate load test and we have achieved 26 Ton/sq.m at 45mm settlement.

5. The construction completed recently in Sept 2022. So far, no problem. We have installed the settlement monitoring instruments in foundatioin and records shows no problem in settlements.

Literature to refer

1. IS 15284 : Design and Construction for Ground improvement

2. Foundation Design Manual for Practicing Engineer By Narayan Nayak is the best book which has detail design of Stone column. You can download from internet or purchase from Amazon which costs you around INR 800-1000.

3. Ground improvent technologies by Nihar Ranjan Patra can be another good reference for design.

Thanks & Regards,
G.Ramesh
+971-585897221
+91-9958366110
Powerchina HDEC Middle east Company,
Dubai.