International Conference on Dam Safety - 2023
14-16September 2023, Jaipur, Rajasthan, India
SEEPAGE CONTROL MEASURES USING CEMENTITIOUS GROUTING OF
MASONRY GRAVITY DAMS – CWPRS EXPERIENCES
SUNIL J. PILLAI1, VIGNESWARAN R2, SARBJEET SINGH3, BALACHANDRAN K.4,
RIZWAN ALI5, JAI PRAKASH MEENA6
1. Mr.R. Vigneswaran, Scientist C, CWPRS, Pune-24, E-mail :r.vigneswaran@cwprs.gov.in
2. Mr.Sunil J Pillai, Scientist C, CWPRS, Pune-24,E-mail :pillai.sj@cwprs.gov.in
3. Dr.Sarbjeet Singh, Scientist C, CWPRS, Pune-24,E-mail : sarbjeetsingh@cwprs.gov.in
4. Mr.K. Balachandran, Asst. Research Officer, CWPRS, Pune-24,E-mail : balchandran@cwprs.gov.in
5. Mr. Rizwan Ali, Scientist E, CWPRS, Pune-24, E-mail :rizwan_ali@cwprs.gov.in
6. Mr. Jai Prakash Meena, RA, CWPRS, Pune-24, E-mail : meena.jp@cwprs.gov.in
ABSTRACT:
Hydraulic structures like dams store water for meeting various needs such as irrigation, drinking,
hydropower etc. and also help immensely to attain self-sufficiency in agro productions, flood control,
drought mitigation and meeting electricity demands. Masonry dams exhibit leakages/seepage due to
poor quality construction, leaching of cementitious material, cracking, design deficiency and ageing
effect. The maintenance of the dams and their preservation in sound health is a matter of great national
and international importance. Maintaining safety of dams is a significant issue which needs to be
continuously monitored to ensure public confidence, protection of downstream areas from flood hazard
and to ensure continued benefits from the national investments. Unwarranted seepages in a dam are a
sign of distress and need to be attended immediately. To restore the structural integrity of the dam and
make the distressed structure serviceable again, various methods are adopted either one or in
combination. Cementitious grouting is one of the most common and effective technique for controlling
seepage and restoring/improving safety of the masonry Dams through reduction in seepage as well as
enhancing strength parameters. This paper discusses the importance of cementitious grouting of
Masonry dams and the various case histories where CWPRS has been successfully associated with viz.
Temghar, Bhatsa, Domihira, Dhamini dams etc.
INTRODUCTION & SEEPAGE IN MASONRY DAMS
In India, many masonry dams were constructed during the past century and the activity increased
manifolds during post independence era. Almost 25% of the total number of dams is masonry gravity
dams. These were preferred, because of the following reasons:-
• It provided large scale employment opportunity for semiskilled and unskilled persons.
• The equipments required for large scale concrete construction were not readily available hence,
leading to delay in execution.
• Sufficient expertise was acquired in building masonry dams during construction of dams such as
Tungabhadra, Khadakwasla etc. which were constructed earlier.
• The other advantage was to utilize locally available material at the project site.
METHODS OF CONSTRUCTION OF MASONRY DAMS
Construction of a masonry dam is of cyclopean type i.e. blocks of stones/ boulders are laid in mortar,
which is customarily dumped from head pans. The stones type ranges from sandstone, Basalt or Granite.
International Conference on Dam Safety - 2023
14-16September 2023, Jaipur, Rajasthan, India
The size of stones varies from 150 mm to 600 mm. Kankar lime or surkhi or cement form cementing
agents in mortar with sand or crushed stones as aggregates. The quality of mortar joints depends on the
workmanship of the mason, the amount and proportion of the mortar and the curing. Since the quality of
work depends on skill of the mason, if not done skillfully, the upstream face joints referred as pointing
permits water to enter the body of dam. The packing behind the stone masonry with small rubble spalls
with mortar is another vulnerable area from where entry of water is possible. Thus there are inherent
limitations for quality control in masonry dams as compared to concrete dams. During the construction
period of masonry dams which ranges between 5 to 15 years, the river diversion works are avoided due
to economy and hence floods pass over the partly constructed sections during this period. The partly
constructed portion acts like weir during this period. Another noticeable feature in masonry dams built
earlier to 1930 is that drainage galleries and expansion joints are not provided. Provision of drainage
galleries help to discharge seepage and reduce uplift and pore pressures. The contraction/expansion
joints help to accommodate the structural movement avoiding tensile cracking due to change in climatic
conditions.
SYMPTOMS AND CAUSES OF SEEPAGE
Whether it is minor or excessive, seepage is a common cause of deterioration of masonry dams. Seepage
in a masonry dam takes place due to a number of factors associated with its construction material,
practice etc. The various symptoms of seepage and deterioration associated with it along with the causes
are listed as below:
• Foundation Deficiency
• Moisture absorption
• Temperature effects
• Leaching
• Excessive uplift pressures
• Construction defects
• Earthquakes / Floods
• Construction joints
DISADVANTAGES OF SEEPAGE IN DAMS
The continuous seepage through masonry dams is very much disadvantageous and results many
problems as listed below:
• Loss of Storage
• Blocking of drains
• Structural Safety
• Dewatering problem
• Aesthetics
CONTROL OF SEEPAGE IN MASONRY DAMS
Nowadys various techniques are in practice to control seepage through masoney dams. But grouting
technique using proper cementious grout mix has been observed very effective and durable in reducing
seepage as well as improving overall safety of the masonry dams. Grouting the body of dam is one of
International Conference on Dam Safety - 2023
14-16September 2023, Jaipur, Rajasthan, India
the effective cure for most of the dams and is being successfully adopted for Shirawta,Watwhan,
Bhandardara and the Radhanagari dams in Maharashtra; Pagara and Sakhya Sagar dams in Madhya
Pradesh and Hemavathy dam in Karnataka. Specifications of grout materials, grout mix proportion,
grout pressures, grout hole spacing, precautions during handling etc. are absolutely necessary for
effectiveness of grouting. Choice of grout materials and mixes is dependent on shape, size and
continuity of the cavities/fissures, seepage water velocities and the strength requirement. Grouting aims
at filling of the cavities/fissures with selected material to impart impermeability and strength to the
masonry. It is necessary that the material should fill the water passages from upstream to downstream to
avoid premature blocking on the downstream side producing uplift pressure. In case of very long dams
without expansion joints, the treatment may be carried out in alternate blocks of suitable length. Usually
cementitious grouts with a variety of admixtures are used. CWPRS has been successfully involved in the
repairs to many Masonry dams and our experience in brief is given in the case studies.
CWPRS EXPERIENCES
TEMGHAR DAM, MAHARASHTRA
86.6 m high Temghar dam has been constructed across Mutha river near Pune district of Maharashtra
during the period March 1997- May 2010. It is a stone masonry gravity dam with 5 m thick septum of
1:3 cement sand mortar colgrout masonry on upstream face which is 3 m thick at base of the dam.
Further, colgrout masonry has been provided in toe region upto EL 667.0 m. Total length of dam is 1075
m and comprises of 72 m long spillway portion in the center and non-overflow portion on either flank.
Considering severity of the problem and hazard potential of the dam, as it is located just on the upstream
of Khadakwasla dam adjoining Pune city, on the request of Project Authorities, Scientists and Officers
from CWPRS carried out several site visits for the inspection of dam from year 2011 onwards. Several
laboratory studies and discussions have been held about the methodology to be adopted for grouting the
body of Temghar Dam to reduce/arrest leakage of water through dam body. The grouting and
subsequent shotcreting of upstream face has reduced the seepage considerably through the dam body.
Reduction in seepage of Temghar dam after grouting and shotcreting
International Conference on Dam Safety - 2023
14-16September 2023, Jaipur, Rajasthan, India
DOMIHIRA DAM, MAHARASHTRA
Domihira dam constructed across Domihira river is located in Palghar district, near Thane in
Maharashtra. The construction work of the dam was completed during the year 2009 and full storage
was impounded during the same year. Just after first impoundment, heavy leakage of water has been
observed through body of spillway portion and the flank walls. The continuous heavy seepage through
dam body has dislodged concrete of spillway glacis and raised apprehensions about the structural safety
of the dam. The cementitious grout mix has been designed based on extensive laboratory and masonry
model studies conducted at CWPRS, Pune to improve mass density, impermeability as well as strength
characteristics of the masonry dam. The dam has been grouted using design mix grout in two stages
from top and upstream face at an effective spacing of 1.5 m c/c. After grouting leakage/seepage of water
through the spillway portion of dam body has stopped completely and significant improvement in mass
density and strength parameters has been achieved.
Reduction in seepage of Domihira dam after grouting
BHATSA DAM, MAHARASHTRA:
Bhatsa dam, is a masonry gravity dam on Bhatsa river near Shahapur, Thane district of Maharashtra.
The height of the dam above lowest foundation is 88.5 m while the length is 959 m and is constructed
with U.C.R. masonry with C.M. 1:3 to 1:5. Bhatsa dam is the major source of water for MCGM
(Municipal Corporation of Greater Mumbai) and TMC (Thane Municipal Corporation). Due to ageing,
distresses in the form of heavy seepage and leaching of mortar have been observed in the galleries of the
dam as well as on downstream face including buttresses throughout the height and along the full length
of the dam. The studies pertaining to design of cementitious grout mix design has been undertaken by
CWPRS, Pune. During site inspections, it has been observed that the seepage has reduced considerably
i.e. by more than 22% (i.e. from 89,640 LPM during Sept 2018 to 67,721 LPM during Dec 2019 as per
recorded data available at site) after nearly 25% of grouting treatment carried out from dam top under
wet and saturated conditions existing inside the dam body indicating the effectiveness of grouting even
under saturated conditions.
International Conference on Dam Safety - 2023
14-16September 2023, Jaipur, Rajasthan, India
Reduction in seepage of Bhatsa dam after preliminary grouting
DHAMNI DAM, MAHARASHTRA:
Dhamni dam of Surya Major Project is a masonry gravity dam constructed across Surya River
(Tributary of Vaitarna River) in VIkramgad Tal, Palghar district of Maharashtra. Surya Project area falls
in Palghar (earlier Thane) district which forms a part of North Konkan Region which lies between the
Sahyadri hills in the East and the Arabian Sea in the West. The height of Dhamni dam above deepest
foundation level is 58.08 m while the length at top of the dam is 623 m. The catchment area of the dam
is 203.30 Sq. km. Water from the dam is released through the tail race of the hydroelectric power house
of 6 MW capacity located at the foot of the dam. A pick-up weir at Kawadas about 5.5 km downstream
of dam has been constructed and two canals namely Left bank canal and Right bank canal originate from
Kawadas for irrigating surrounding areas. The work of the dam construction has been completed in the
year 1990. Due to ageing, distresses in the form of heavy seepage and leaching of mortar have been
observed in the galleries of the dam as well as on downstream face throughout the height and along the
full length of the dam, which might have caused significant reduction of strength parameters and
affected mass density. Therefore, for controlling loss of water and improving structural integrity of the
dam, remedial measures such as dam body grouting and shotcreting at upstream face of the dam were
finalized by Project Authorities. Prior to commence the execution at site, extensive laboratory studies at
CWPRS for grout mix and shotcrete, have been carried on many combinations of mix design by varying
proportions of cement, flyash, silica fume, admixtures and quantity of water. Due to dam body grouting
and shotcrete in upstream face of Dhamini dam in Maharashtra, the seepage/leakage through the dam
portion has been observed to be reduced considerably. The overall seepage rate has reduced from 197
LPS to about 41 LPS after the successful grouting and shotcreting.
Downstream face of Dhamini dam before and after grouting & Shotcreting
International Conference on Dam Safety - 2023
14-16September 2023, Jaipur, Rajasthan, India
ONGOING STUDIES IN CWPRS FOR CEMENTITIOUS GROUTING
Based on the success of previous studies, the Project Authorities has requested CWPRS to conduct
cementitious grouting of the following dams for which the studies are in progress:
• Warna Dam, Maharashtra
• Dudhganga Dam, Maharashtra
• Radhanagari dam, Maharashtra
• Mahi dam, MP
• Tillari Dam, Maharashtra
• Ujjani dam, Maharashtra
CONCLUSIONS
Based on the studies discussed in this paper following conclusions are drawn:
1. Dam body grouting using proper mix design is a well proven, economical and effective tool to
control seepage and improve structural integrity of the distressed masonry dams.
2. Design of cementitious grout mix is important and necessarily be done by conducting laboratory
tests on different materials. After conducting the suitability tests in laboratory by using many mix
proportions, a suitable design mix is arrived at for carrying out grouting in the field.
3. The seepage has considerably reduced in many grouted masonry dams namely Temghar, Bhatsa,
Domihira, Damini dams using cementitious grout mix design carried out at CWPRS.
ACKNOWLEDGEMENTS
Authors express their sincere thanks to Dr. R.S. Kankara, Director, CWPRS, Scientist E, for guidance,
encouragement and valuable suggestions during the preparations of the paper. Thanks are also due to
the various Project Authorities for awarding the studies to CWPRS, Pune.
REFERENCES
• CW&PRS Technical Memorandum on “Dam Safety and Rehabilitation”, May 2015.
• CW&PRS Technical Memorandum on “Controlling Seepage through Hydraulic
Structures”, July 2015.
• Rizwan Ali, SunilJ Pillai, R. Vigneswaran, et al. “Assessment of suitable cementitious
grout mix design for controlling seepage in distressed Masonary dams – A case
study”, for inclusion in “International Dam Safety Conference-2018” held at
Thiruvanthapuram, Kerala during January 2018.
