Index 1.OBJECT.............................................................................................................1 2.INTRODUCTION.................................................................................................1 3.SCOPE OF WORK:...............................................................................................2 4.EXPLORATION PROGRAMME:...............................................................................2 5.METHODOLOGY OF FIELD INVESTIGATION:...........................................................4 5.1.Boring:...........................................................................................................4 5.2.Sampling:.......................................................................................................4 5.2.1.Disturbed Sampling (DS):..............................................................................4 5.2.2.Undisturbed Sampling (UDS):.........................................................................4 5.2.3.Transportation and storage of samples:...........................................................5 5.3.Standard Penetration Test (SPT):......................................................................5 5.4.Drilling in rock:...............................................................................................6 5.5.Ground Water Level Measurement:....................................................................7 6.STANDARDS AND GUIDELINES FOR FIELD INVESTIGATIONS:..................................7 7.GEOTECHNICAL LABORATORY TESTING:...............................................................8 8.GEOTECHNICAL ASSESSMENT AND FOUNDATION FEASIBILITY.................................. ...........................................................................................................................9 8.1.DEPTH OF FOUNDATION...................................................................................9 8.1.1.FOUNDATION IN SOIL...................................................................................9 8.1.2.FOUNDATION IN ROCK................................................................................11 9.OPEN/ SHALLOW FOUNDATIONS IN SOIL............................................................11 9.1.Net safe bearing capacity from shear consideration:...........................................11 9.1.1.For Clay Soils (Φ = 0):................................................................................11 9.1.2.For C - Φ soils:...........................................................................................11 9.1.3.Reduction Factors:......................................................................................12 9.2.Net Safe Bearing Capacity:.............................................................................12 9.3.Determination of Safe Bearing Capacity (SBC) from SPT 'N' value considerations...12 10.PILE FOUNDATIONS........................................................................................15 10.1.Capacity of Piles in Intermediate Geo-material and Rock:..................................15 10.2.Ultimate Capacity of Pile in Soils:...................................................................17 10.3.Lateral Capacity of Pile..................................................................................18 11.SUMMARY OF FOUNDATION DETAILS:...............................................................20 12.LIMITATIONS:................................................................................................25 ANNEXURE Individual Reports of all Structures
Preparation of Detailed Project Report for Up-gradation of Ausa – Waranga & Wardha – Butibori Section of NH361 in the state of Maharashtra.
FINAL DETAILED PROJECT REPORT SUB SOIL EXPLORATION & ANALYSIS REPORT WARDHA-BUTIBORI
SUB SOIL EXPLORATION & ANALYSIS REPORT 1. OBJECT Conducting detailed Subsoil Investigation and recommendation of Net Safe Bearing Capacity (SBC) for various structures of Ausa-Waranga & Wardha - Buttibori section of NH361 in the state of Maharastra. The entire project awarded consists of following four packages:
•
Ausa – Chakur (58.2 km)
•
Chakur – Loha (61.8 km)
•
Loha – Waragaphata (70.7 km)
•
Wardha-Butibori (60 km)
The present report consists of detailed engineering services for Wardha – Buttibori section (NH – 361) from Km 85+300 to Km 28+800 (i.e., Salad to Butibori). This Report Consists of:
Introduction
Scope of work
Methodology of subsurface Investigation
Sub soil profile
Analysis & sample Design
Foundation Recommendations
2. INTRODUCTION This report presents the results of field explorations and Geotechnical engineering studies performed for proposed major bridges (MJB), minor bridges (MIB) and vehicle underpasses (VUP) in various predetermined locations. The purpose of the explorations
and
studies
is
to
identify
subsurface
conditions
and
formulate
Geotechnical recommendations for design and construction. The main text of the report includes description of field explorations, laboratory testing, subsurface conditions, conclusions and recommendations based upon review of existing data, engineering studies and analysis. Field and Laboratory works are conducted based on Indian Standard specifications and, as per the requirement of project.
1
Preparation of Detailed Project Report for Up-gradation of Ausa – Waranga & Wardha – Butibori Section of NH361 in the state of Maharashtra.
FINAL DETAILED PROJECT REPORT SUB SOIL EXPLORATION & ANALYSIS REPORT WARDHA-BUTIBORI
3. SCOPE OF WORK: The scope of subsoil Investigation is to ascertain Geotechnical and geological properties of substratum for design and construction of various types of foundations. It is proposed to have exploration by drilling of boreholes at various locations of given structures. Accordingly the exploration program of boreholes are taken upto a maximum depth of 19.5 m or 3 m into hard rock whichever occurs earlier. Undisturbed, Disturbed and Rock samples were collected appropriate to ground conditions and transported them to Geotechnical laboratory. Laboratory tests are conducted to determine the Index and Engineering properties of soil, rock and suggested the Net Safe bearing capacity of the soil on which structures are to be constructed.
Engineering analysis was carried out for recommending the location
and Net Safe Bearing Capacity of foundation for the proposed structures. 4. EXPLORATION PROGRAMME: Sub-Soil Investigation Plan S. No. Existing chainage
Type of Structure
No of Boreholes
1
28+750
523+305
Half Trumpet
2
2
36+233
517+060
4 Lane VUP
1
3
38+853
514+515
MIB
1
4
39+810
513+566
MIB
1
5
43+607
509+760
MIB
1
6
43+905
509+462
MIB
1
7
44+830
508+583
MIB
1
8
45+789
507+773
2 Lane VUP
1
9
47+126
506+316
MIB
1
10
49+552
503+860
MIB
1
501+930
2 Lane VUP
1
501+093
MIB-2
1
11 12
Kelzar Bypass
13
55+052
498+449
MIB
1
14
56+979
496+428
MIB
2
15
58+550
494+892
MIB
1
493+270
Major Bridge
5
493+132
MIB-2
1
492+914
MIB-1
1
492+204
2 Lane VUP
1
487+542
MIB
1
16 17 18
Seloo Bypass
19 20
2
Proposed Chainage
65+961
Preparation of Detailed Project Report for Up-gradation of Ausa – Waranga & Wardha – Butibori Section of NH361 in the state of Maharashtra.
S. No. Existing chainage
FINAL DETAILED PROJECT REPORT SUB SOIL EXPLORATION & ANALYSIS REPORT WARDHA-BUTIBORI
Proposed Chainage
Type of Structure
No of Boreholes
21
67+122
486+368
MIB
1
22
67+725
485+759
MJB
9
23
72+328
477+600
2 Lane VUP
1
24
76+650
474+016
2 Lane VUP
1
25
Salod realignment
471+516
ROB
2
26
Salod reallignment
468+038
4 Lane VUP
1
Field Tests
Standard Penetration Test (SPT) was conducted at every 1.5m depth interval in boreholes as per IS: 2131-1981.
Disturbed Samples (DS) and undisturbed Samples (UDS) were collected as per IRC 78 – 2000 guidelines
Drilling in soft rock, weathered rock and in hard rock was carried out by diamond core drilling method using double tube core barrels of Nx size and obtained the rock cores.
Ground Water table was observed in each bore hole as per IS : 6935 - 1973
Following Laboratory Tests are Conducted on selected samples of Disturbed and Undisturbed soil samples
Moisture content & Specific Gravity
Bulk Density
Grain Size Analysis
Atterbergs Limits
Free Swell Index
Triaxial Shear Properties – Cohesion, C and Friction Angle, Φ
Following Laboratory Tests are Conducted on selected Rock samples 3
Preparation of Detailed Project Report for Up-gradation of Ausa – Waranga & Wardha – Butibori Section of NH361 in the state of Maharashtra.
Moisture content, Porosity & Density
Specific gravity
Uniaxial Compression test
FINAL DETAILED PROJECT REPORT SUB SOIL EXPLORATION & ANALYSIS REPORT WARDHA-BUTIBORI
5. METHODOLOGY OF FIELD INVESTIGATION: The field exploration methods, sampling requirements, types and frequency of field tests are performed based on project design requirements. Accordingly, we have developed the overall investigation plan which enables us to obtain the data needed to define subsurface conditions and perform Engineering analysis and design. 5.1. Boring: Drilling of boreholes was carried out at specified locations to obtain information about the subsoil profile, its nature, strength and also to collect soil samples for strata identification and conducting laboratory tests. The sequence of boring was planned after ascertaining preliminary nature of subsoil profile. Boring is carried out as per the provisions given in IS: 1892-1979. 5.2. Sampling: All the accessories used for sampling and the method of sampling adopted confirms to IS: 2132. All the disturbed and undisturbed samples collected in the field have been classified at the site as per IS : 1498. 5.2.1. Disturbed Sampling (DS): Disturbed soil samples were collected from bore holes at regular intervals to determine the soil type, grain size distribution, Atterberg limits and soil classification. 5.2.2. Undisturbed Sampling (UDS): In each borehole, undisturbed samples are collected at every change of strata. Undisturbed sampler tubes are made up of 100mm diameter, 450mm long MS tubes provided with sampler head with ball check arrangement. Samples are collected in such a manner that the structure of soil and its moisture content do not get altered. At few locations, the sampling tubes could not be pushed into the soil because of hard consistency. The specifications for the accessories used for sampling and the sampling procedure adopted conforms to IS:1892 and IS:2132. Undisturbed samples are used to determine the shear parameters, natural moisture content and unit weight.
4
Preparation of Detailed Project Report for Up-gradation of Ausa – Waranga & Wardha – Butibori Section of NH361 in the state of Maharashtra.
FINAL DETAILED PROJECT REPORT SUB SOIL EXPLORATION & ANALYSIS REPORT WARDHA-BUTIBORI
5.2.3. Transportation and storage of samples: Undisturbed Samples are hand carried holding them in vertical. Shipping and storage was done vertically in most of the situations. Samples are kept as near to ground temperature during shipping. Samples are stored in a dark humid room having 90 94% humidity to prevent loss of moisture. 5.3. Standard Penetration Test (SPT): Standard Penetration Test (SPT) was conducted at different depths in all boreholes. For shallow depths SPT was conducted at close intervals of 1.5m. SPT split spoon sampler of standard dimensions was driven into the soil from borehole bottom using 63.5kg hammer falling from 75cm height. The SPT weight was mechanically lifted to the specified height and allowed to free fall. Blow count for each of three 15cm penetrations was recorded and the N is reported as the blows count for the last 30cm penetration of the sampler leaving the first 15cm penetration as seating drive. When the number of blows exceeded 50 to penetrate the first or second 15cm length of the Sampler, the SPT ‘N’ is regarded as more than 100 as described in IS: 2131 - 1981. SPT refusal is recorded when there is no penetration of the sampler at any stage and also when a rebound of the sounding system is recorded. Samples from the SPT split spoon sampler was preserved in polythene covers and transported to the laboratory. One more polythene cover was provided to prevent the loss of moisture during the transit. The degree of denseness or looseness of natural deposited cohesionless soils can be measured in terms of their relative density. SPT ‘N’ values are correlated with relative density of non - cohesive stratum and with consistency of cohesive stratum. Correlation for Sand/ non-plastic Silt
5
Correlation for Clay/ Plastic soils
Penetration Value (N)
Relative Density
Penetration Value (N)
Consistency
0 - 4 Blows
Very Loose
0 - 2 Blows
Very Soft
4 - 10 Blows
Loose
2 - 4 Blows
Soft
10 - 30 Blows
Medium Dense
4 - 8 Blows
Medium
30 - 50 Blows
Dense
8 - 15 Blows
Stiff
>50 Blows
Very Dense
15 - 30 Blows
Very Stiff
>30 Blows
Hard
Preparation of Detailed Project Report for Up-gradation of Ausa – Waranga & Wardha – Butibori Section of NH361 in the state of Maharashtra.
FINAL DETAILED PROJECT REPORT SUB SOIL EXPLORATION & ANALYSIS REPORT WARDHA-BUTIBORI
5.4. Drilling in rock: For drilling in rock, drilling was advanced by rotary core drilling method using double tube core barrels with T.C bit or diamond bit as per the guidelines of IS:6926-1996. The maximum length of drill run maintained is 1.0m. At the end of each run, the drill rod string with core barrel is extracted from the
from the Borehole and core is recovered
core barrel. The percentage of core recovery is recorded
and the core
pieces are transferred to the core box duly numbered and labeled properly. The selected core samples are sent to the laboratory for conducting tests. The rock core samples are preserved and stored in wooden core boxes as specified in IS:4078 – 1980 Rock classification in terms of weathering, state of fractures and strength is carried out in the following manner. (As per IS: 4464) Term Fresh
Description No visible sign of rock material weathering; perhaps slight discoloration on major discontinuity surfaces
Discoloration indicates weathering of rock material and discontinuity surfaces. All the rock material may be Weathered discolored by weathering. Slightly
Less than half of the rock material is decomposed or Moderately disintegrated to a soil. Fresh or discolored rock is Weathered present either as a continuous framework or as core stones. More than half of the rock material is decomposed or disintegrated to a soil. Fresh or discolored rock is Weathered present either as a discontinuous framework or as core stones Highly
Completely All rock material is decomposed and / or disintegrated to soil. The original mass structure is still largely Weathered intact. Residual Soil
6
All rock material is converted to soil. The mass structure and material fabric are destroyed. There is a large change in volume, but the soil has not been significantly transported.
Grade Interpretation I
CR > 90 %
II
CR between 70% to 90%
III
CR between 51% to 70%
IV
CR between 11% to 50%
V
CR between zero to 10%
VI
CR = Zero But N > 50
Preparation of Detailed Project Report for Up-gradation of Ausa – Waranga & Wardha – Butibori Section of NH361 in the state of Maharashtra.
FINAL DETAILED PROJECT REPORT SUB SOIL EXPLORATION & ANALYSIS REPORT WARDHA-BUTIBORI
RELATION BETWEEN RQD AND IN-SITU ROCK QUALITY Rock quality is further measured by frequency of natural joints in rock mass. Rock Quality Designation (RQD) is used to define state of fractures or massiveness of rock. Following table defines the quality of rock mass. RQD CLASSIFICATION
RQD (%)
Excellent
91-100
Good
76-90
Fair
51-75
Poor
25-50
Very Poor
