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IS 11207:1985 is the Indian Standard (BIS) for recommendations for instrumentation for rock mechanics. This standard provides recommendations for the selection, installation, and operation of instruments used in rock mechanics. It covers the monitoring of various parameters such as deformation, strain, stress, temperature, and groundwater pressure to assess the behavior of rock masses during and after construction of major civil engineering projects like tunnels, dams, and underground cavities.
Provides recommendations for the selection, installation, and monitoring of various instruments used in rock mechanics applications, including underground excavations.
Overview
Status
Current
Usage level
Specialized
Domain
Geotechnical — Tunneling and Underground Structures
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
Practical Notes
! The selection of an instrument is critical and should be based on the project requirements, geological conditions, expected magnitude of change, and required precision.
! Proper installation, calibration, and establishment of a reliable baseline reading before construction activities commence are paramount for acquiring meaningful data.
! Data interpretation requires a strong understanding of the instrument's principles, its limitations, and the geological and construction context of the site.
ISRM Blue Book (2007)International Society for Rock Mechanics (ISRM), International
HighCurrent
The Complete ISRM Suggested Methods for Rock Characterization, Testing and Monitoring: 1974-2006
A compilation of suggested methods for a wide range of rock mechanics monitoring instruments, similar to the scope of IS 11207.
ISO 18674 SeriesInternational Organization for Standardization (ISO), International
HighCurrent
Geotechnical investigation and testing — Geotechnical monitoring by field instrumentation
A modern, multi-part standard covering the same topics as IS 11207 but with separate parts for each instrument type (e.g., extensometers, inclinometers).
ASTM D4403/D4403M-19ASTM International, USA
MediumCurrent
Standard Practice for Extensometers Used in Rock
Directly corresponds to the extensometer section of IS 11207, covering selection, installation, and monitoring.
ASTM D4622-18ASTM International, USA
MediumCurrent
Standard Test Method for Rock Mass Monitoring Using Inclinometers
Directly corresponds to the inclinometer section of IS 11207, covering procedures for monitoring with inclinometers.
Key Differences
≠IS 11207 (1985) is a single, monolithic document covering all instruments, whereas modern standards like the ISO 18674 series are modular, with a general part and separate, highly detailed parts for each instrument family.
≠The Indian standard describes technologies prevalent in the 1980s (e.g., mechanical dial gauges, basic electrical resistance). Modern international standards extensively cover current technologies like vibrating wire (VW), fiber optic sensors (FOS), and automated data acquisition systems (DAS).
≠Modern standards (e.g., ISO 18674 series) define specific performance classes and quantitative requirements for instrument accuracy, resolution, and drift. IS 11207 provides more general, descriptive recommendations.
≠International standards include formal requirements for a 'Geotechnical Monitoring Plan', data management, processing, and reporting, reflecting modern digital workflows which are not detailed in the older IS code.
Key Similarities
≈All standards are based on the same fundamental rock mechanics principles for measuring displacement, strain, stress, and pore pressure to evaluate rock mass behavior.
≈The basic categories of instruments covered are consistent, including extensometers, inclinometers, piezometers, stress meters, and load cells, as their primary function remains unchanged.
≈The core recommendations for successful instrument installation, such as proper borehole preparation, grouting techniques for sensor coupling, instrument protection, and the importance of establishing a stable initial 'zero' reading, are common across all standards.
≈The stated purpose of instrumentation is identical: to verify design assumptions, monitor safety during construction, and provide long-term performance data for structures in and on rock.
Parameter Comparison
Parameter
IS Value
International
Source
Extensometer Accuracy (Mechanical)
Desirable accuracy of 0.025 mm
Precision should be better than 0.1 mm
ISRM Suggested Method (1984)
Grout Water-Cement Ratio for Anchors
0.4 to 0.5
Typically 0.4 to 0.5
ASTM D4403/D4403M-19
Inclinometer Casing Spiral/Twist
Should not exceed 0.25 degrees per 3 m
Maximum twist of 1 degree per 3 m is often specified for standard casing
ASTM D4622-18
Inclinometer Survey Interval
Readings at 0.5m or 1.0m intervals
The measurement interval shall correspond to the gauge length of the probe (e.g., 0.5 m)
ISO 18674-2:2016
Piezometer Type
Describes open standpipe, pneumatic, and electrical resistance types
Primarily focuses on modern types like vibrating wire and pneumatic, with detailed performance criteria
ISO 18674-4:2018
Data Acquisition
Focuses on manual readings with portable readout units.
Includes detailed provisions and requirements for Automated Data Acquisition Systems (DAS) and remote monitoring.
ISO 18674-1:2015
⚠ Verify details from original standards before use
Key Values0
No quick reference values available for this code yet.
Tables & Referenced Sections
Key Tables
No tables data
Key Clauses
Clause 3: Measurement of Deformations
Clause 4: Measurement of Strains
Clause 5: Measurement of Stress
Clause 6: Measurement of Temperature
Clause 7: Measurement of Ground Water Pressure and Flow
What instrument is used to measure lateral movement of a slope?+
An inclinometer is used to measure lateral deflections or deformations in soil and rock masses. (Clause 3.2.3)
How can I monitor the stress changes in the rock around a tunnel?+
Borehole stressmeters (e.g., vibrating wire stressmeter) or flat jacks can be installed to measure the change in stress in the rock mass. (Clause 5)
What is the difference between an extensometer and an inclinometer?+
An extensometer measures axial displacement (movement along the axis of the instrument), while an inclinometer measures lateral displacement (movement perpendicular to the axis of the instrument).
What is a piezometer used for in rock mechanics?+
A piezometer is used to measure pore water pressure or groundwater levels within the rock mass, which is crucial for stability analysis. (Clause 7)