Selection of Retaining Walls in Hill Areas_Indian Standards

इंटरनेटमानक Disclosure to Promote the Right To Information Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public. “जान1 का अ+धकार, जी1 का अ+धकार” “प0रा1 को छोड न' 5 तरफ” “The Right to Information, The Right to Live” “Step Out From the Old to the New” Mazdoor Kisan Shakti Sangathan Jawaharlal Nehru IS 14458-1 (1998): Guidelines for retaining wall for hill area, Part 1: Selection of type of wall [CED 56: Hill Area Development Engineering] “!ान $ एक न' भारत का +नम-ण” Satyanarayan Gangaram Pitroda “Invent a New India Using Knowledge” “!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता ह” है” ह Bhartṛhari—Nītiśatakam “Knowledge is such a treasure which cannot be stolen” . . 9 BAHADUR SHAH ZAFAR NEW DELHI 110002 MARG Price Group 4 .020 0 BIS 1998 BUREAU MANAK May 1998 OF INDIAN STANDARDS BHAVAN.IS 14458 (Part 1) : 1998 ( Reaffirmed 2002 ) Indian Standard RETAINING WALL FOR HILL AREA GUIDELINES PART 1 SELECTION ICS OF TYPE OF WALL 93. the final value. Retaining wall is a structure used to retain backfill and maintain difference in the elevation of the two ground surfaces. For the purpose of deciding whether a particular requirement of this standard is complied with. Similarly the cost of a breast wall is several times more than a non-walled cut slope. one me&e of extra width in filling. This standard (Part I)_is. . However. CED 56 FOREWORD This Indian Standard (Part 1) was adopted by the Bureau of Indian Standards. after the draft finalized by the Hill Area Development Engineering Sectional Committee had been approved by the Civil Engineering Division Council. considering maintenance cost. Kathmandu. the use of retaining walls on hill roads and terraces becomes essential. Retaining wall may be effectively utilized to tackle the problem of landslide in hill area by stabilizing the fill slopes and cut slopes. progressive slope instability and environmental degradation from unprotected heavy excavations. shall he rounded off in accordance with IS 2 : 1960 ‘Rules for rounding off numerical values (revised)‘. Assistance has also been derived from Mountain Risk Engineering Handbook. The composition of technical committee responsible for the formulation of this standard is given at Annex A. therefore. From the initial construction cost considerations. requiring retaining walls. costs much more than constructing the same wjdth by cutting inside the hill. considerable assistance has been provided by International Centre for Integrated Mountain Development. observed or calculated. expressing the result of a test or analysis. being formulated to provide necessary guidance in selection of retaining walls for stability of hill slopes. the other parts of the standard being: Part 2 Design of retaining/breast Part 3 Construction walls of dry stone walls Part4 Construction of banded dry stone walls Part 5 Construction of cement stone walls Part 6 Construction of gabion walls Part 7 Construction of RCC crib walls Part 8 Construction of timber crib walls Part 9 Design of RCC cantilever wall&-type walls Part 10 Design and construction wall/buttressed of reinforced earth retaining walls In the formulation of this standard. The number of significant places retained in the rounded off value should be the same as that of the specified value in this standard.Hill &ea Development Engineering Sectidnal Committee. (mtind) 1 . 1 DIFFERENT TYPESOFRETAININGWALLS. 2.2 The classification of retaining walls with respect to their design and probable behaviour of construction medium may be as follows: a) Bin walls i) Rectangular ii) Circular iii) Cross tied b) Crib walls i) Concrete crib ii) Timber crib Gabions walls and wire crated/sausage walls d) Cement masonry walls d Dry stone masonry walls f-l Drum walls g) Reinforced backfill walls NOTE .’ FAILURE I (a) GRAVITY PLANE WALL ASS. for the purpose of imparting stability to the slopes in hill areas. They are mainly meant to support the active or passive earth pressure from the assumed failure wedge above the base of the wall.The retaining walls are normally not intended to stabilize slope failures. 1) as follows: a) Gravity walls b) Tie back walls ORIGINAL GROUND Driven cantilever walls Reinforced earth walls RCC walls . 2 CLASSIFICATION c> 2. The stabilization of existing or probable failure planes caused by landslides.1 The retaining walls shall be classified on the basis of type of construction and mechanics of behaviour (see Fig.~AE&FAILURE IN BACK-FILL WALL GROUTED ANCHOR 1 (b) TIE BACK~WALL FIG. Only the fill slopes and cut slopes could be stabilized/retained by retaining walls. flows and falls require separate treatment and specific design approaches.IS 14458 (Part 1) : 1998 Indian Standard RETAINING WALLFORHILLAREAGUIDELINES PART 1 SELECTION OF TYPE OF WALL 1 SCOPE c) d) e) This standard (Part 1) covers the guidelines for selection of various retaining walls to suit the site conditions. the excavated material shall be disposed off at suitable identified sites.1. High walls may.1. be provided. surface/subsurface drainage system. walls may not be designed for earthquake forces.4 A retaining wall on a thin talus slope may not be able to prevent the failure of entire talus slope during monsoon because of the quick rise of water table above the relatively impervious bed rock. the guidelines given in 311. Walls with dip at the base towards hillside will reduce the base width in seismic areas. 3. 3 SELECTION OF TYPE QF WALLS 3.IS 14458 (Part 1) : 1998 ASSUME0 FAILURE 1 (c) DRIVEN CANTILEVER WALL REINFORCING 1(e) RCC WALLS 1 id) REINFORCED EARTH WALL TYPES OF RETAINING WALLS FIG. slope of backfill. local skill. 3.1.6 Improper backfill and poor drainage behind the wall involve complicated drainage conditions which are normally-not considered in normal design. 3.14 shall be considered for selection of the type of~retaining wall to be constructed for the purpose of imparting stability to the slopes in hill area. therefore.1. However.1 For hilly roads.1to 3. the choice of wall depends on local resources. Hence during construction of retaining walls. 3.5 The construction of series of retaining walls one above another on an unstable or marginally stable slope shall be avoided as it adds more pressure on the lower walls destabilizing the slope contrary to the aim of stabilizing the slope. 1 DIFFERENT i) Reinforced earth ii) Fabric h) Anchored walls i) Horizontal sheet pile ii) Vertical sheet pile iii) H-pile. hill slope angle. 3.1. foundation conditions. In such cases.7 The practice of undertaking wall construction after road/hill cutting poses the problem of disposal of excavated material and loss of top soil that could otherwise be used for vegetation. 3. Froper drainage behind the walls shall.1.3 Front battered retaining walls are many times more expensive than back battered walls in steep hilly areas.1. compatibility of materials and sefsmicity of the region (see Tables 1 and 2). therefore.1. timber logged j) RCC walls i) Cantilever ii) L-type iii) Buttressed wali iv) Frame retaining walls terraces unless justified by risk analysis. 3.excessive wall dimensions.1 In general. being of low volume. be avoided by alternative geometric designs of roads and 2 .2 Earthquake considerations lead to . etc. It is economical ‘ to repair failed walls after earthquake. unstable slope shall be stabilized by afforestation. 1.12 Reinforced earth is normally used as reinforced fill platform for road. These are also suitable for hill slope angles from 30” to 6V’. breast walls and timber crib are economical but least durable.1. height less than 4 m in low volume roads. Batter (negative) of the backfill side reduce base width of the wall significantly.8 Breast walls are more economical for cut slopes.1. are susceptible to earthquake 3. where higher walls are needed. RCC walls. 3.11 Banded dry stone masonry (height 5 6 m) and cement masonry walls are most durable but being non- ductile structures. . These are most susceptible damages. These are not suitable for terrace development because of short life.1. non-ductile s@uctur-es. to earthquake 3. These can take considerable differential settlement and some slope movement.13 Timber crib.IS 14458(Part 1) : 1998 3.9 Dry stone retaining walls.1.14 Cement masonry. dry stone masonry walls may be provided for hill slope angle less than 30” and. 3.1. damages.10 Gabion/wire crated walls shall be used in case of poor foundation or seepage conditions.1. 3. high cut slopes and terraces. Gabion walls shall be considered for high volume roads. 3. Generally it is not used as preventive method of slope support. Stone shape important. Compact granular back fill in layers (< 15 cm). Weep holes 15x 15 cm size at l-2 m c/c.7 H s Front batter 4:l T Back batter nward dip of foundation 0 N P R U C T 1 0 Foundation dram depth below 0. No weathered stone to be used.7-0.1) s Diagrammatic Cross-section C 0.6-0. Cement masonry bands of 50 cm thickness at 3 m c/c. Other specifications as for dry stone Wall.7-0. Ecologitally unacceptable.6-0. Provide drainage layer in case oi seepage problems. Use H type gabion wall.8 H vertical varies IO:1 6:l 611 3:l 4:l varies vertical varies varies varies 3:l 1:4 1:3 1:3 horizontal or 1:6 1:6 1:6 horizontal 0. Specify maximum/n&timum stone size.5m 0. Stones to be hand packed.5 m lm 0.0 m lm l-2m 4 m or 0. Specify spacing of reinforcement grids.6521 4 m or 0.55-0.65 H 6.0 m 0.5-1.6-1.75 H 0.5 m Top width 2m 0. Hand packed stones in back till. 10% of all headers to extend into fill.Use geogrid for H <4 m and tensur grid for H> 4 m. blocky preferable to tabular.5-l m 0. . Use long bond stones.0m Base width - 0.8 m 0.5-0.6-1. No Boulder Pitching Set stones along foundation bed.65 H 0.5-l m 0.5-0.Table E 1 Selection of Retaining Walls (Clause 3. GranularbacktilIprcfered.5-I m Range of height 3-9 m l-6m 6-8 m l-10m l-6m 6-10 m 3-25 m Hill slope angle <30” <35” 20” 35-60 35-60 35-60 <35 N Toe protection rock/soil N 0 T E S Generai in case of soft Boulder pitching Timbers 15 cm cp with stone rubble well packed behind timbers. rubble 50 cm backing for drainage. 2. Assume surcharge on road of 2T/m*. . Used both as cut slope and till slopes support. Least durable Most durable Application Non ductile structure most susceptible to earthquake damage 1. 3.1. 3. Drainage of wall bases not shown. Breast wall is more economical for cut slope. Provide 15 cm thick gravel layer in case of clayey foundation. Can take differential slope movement settlement and Very flexible structures Huge potential used more a stable reinforced till platfort for road rather than preventiv method of slope support. Foundations to be stepped up if rock encountered. foundation conditions and also shape of back till wedges as illustrated in diagrams and compatibility of materials. All walls require durable rock filling of small to medium size. local skill. Design as conventional retaining walls. hill slope angle. Choice of wall depends on local resources. 2. 2m 35-60 35-70 35-60 35 No No No . Use vertical single drum for 0. slope degr&ation ptutic~larly where vulnerable structures are ofrisk.5 mQ. typical dimensions shown rely both on well-dmined back_till and good foundation conditions. Total system of measures is far more effective than individual measures.3H 1 0.5 m thickatl. Wall construction requires special skills and practical labour.5-l m 0.5 1Topwidth 0. check drains. devetment walls have uniform sectiondo.25 m 3-8 m I-10m 1-8 m 2. Anchor drumwalls on sides. I Detailed design is necessary in case of soil slopes and walls higher thah 6 m and poor foundation cohditions. ocherwise as for retaining Walk. i Hill slope angle 6m 4m / 3m 35-60 Toe protection in case of soft rock/soil No pitching I I 1Cement masonry (1:6) 1 Weep holes 15 x 15 cm Pack stone along bands of 0. Back batter Gabion walls should be used in case of poor foundation/seepage conditions. turfing. Step in frontface 20-50 cm wide.5m No 3 to5:1 ++---I’. They can take considerable differential settlement and some slope movement. sealing of cracks. @iI1debris material.7 m height.5m 1 0.23H Front batter The. Other measures should also be taken.5 m 0.75 m tickness for batterof 2:l OTnwe. All preventive measures should be implemented in one season. 2 -II 3:1 a:1 51 3:1 3:l Inward dip of foundation 1:3 1:4 I:5 I:3 1:3 I:5 0. for example. major erosion.5m / 0. 0. sand (1:6) minimum stone size.Table 2 Selection of Breast Walls (Clause 3. Specify ness at 3 m c/c. 4.29H Base width 1.5 / 0. .1) Breast Walls/Revetment Walls Type Banded Dry Stone Masonry (3) Dry Stone (2) cement M=ry (4) T (7) -i0. rock fall. benching of cut slopes in soft rocks.33H 0. Curing of masonry walls generally not feasible in hills due topaucity of water. use grade 1:lO. etc.5 0. Little used Most dumbWcostly Least durabIe/ economical General Application Ronduuiie sbuclures most susceptibleto eatdquake damage. i Foundation . depth below drain i Range of height . Sectionshaped to stat var Quite dnmblc/costlier Or Very flexible Revetmentsare used to prevent onlj. Cement bond stones. _.5m 0. 0.5-2mcIcand foundation bed. 5. SINGH(Alrernure) SHRILAKHBIRSINGHSONKHLA DR P. Roorkee ‘DR SUDHIRKUMAR(Alternure) PROFC. NARULA SHRIS. C. SAINI DR BHAWANISINGH Central Mining Research Institute. GOPALAKRISHNAN(A~~~~~Z~~~) ( Continued on puge 8 ) . C. M. Pant Institute of Himalayan Environment and Development. MAITRA PROFARVINDKRISHAN(Abemute) Ministry of Railways. C. DEPUTYSECRETARY(T). Dhanbad University of Roorkee. SINGH Department ofScience and Technology. K. Almora School of Planning and Architecture. New Delhi SHRIG. HARBOLA SHRIP.IRC (Alternufe) Sectional Committee. SINHA SHRID. DGBR) (N & W) DIRECXOR (SARDARSAROVAR)(Alternate) DR R. New Delhi IIT. BHAGAT(Alfernute) Central Building Research Institute. New Delhi DR G. Debra Dun . TOLIA(Alternute) DR K. New Delhi Society for Integrated Development of Himalayas. Jorhat SHRIKIREETKLIMAR PROFA. SENGWTA(Alternnte) Building Materials & Technology Promotion Council. New Delhi Indian Meteorological Department. B. PATHAK(Alremute) Forest Survey of India. BORTHAKUR (Abernufe) SHRIS. Roorkee Ministry of Surface Transport. K. JAGANNATHA RAO SHRID. S. KAUL Regional Research Laboratory. RAO SHRIP. DUBEY DR D. SAH SHRIJ. C. K. GOPALAKRISHNA (Alternate) Sikkim Hill Area Development Board. S. S.SHRIR. Calcutta SHRIMATI M. New Delhi National Institute of Hydrology. Army Headquarters. CHAKRABORT~ DEPUIYDIRECTOR GENERAL(D & S DTE. Roorkee DR P. HCD CED 56 Representing Chairman DR GOPALRANJAN Members SHRISHEIKHNAZIRAHMED PROFA. New Delhi G. JAIN(Alremure) SHRIBH~~P SINGH SHRIR. Assam Public Works Department. KALITA SHRIB. New Delhi Directorate General Border Roads (D&S). S. UPADHYAY(Alternate) SHRIPAWANKUMAR GUAVA Indian Roads Congress. P. SRINIVAWLU North-Eastern Regional Institute of Water and Land Management. K. PRADHAN SHRIP. C. PARTHASARATHY Engineer-in-Chief’s Branch.IS 14458 (Part 1) : 1998 ANNEX A (Foreword) Hill Area Development Engineering University of Roorkee. Gangtok Central Road Research Institute. L. Roorkee Public Works Department. K. Mussorie PIELDCOORDINATOR (Altemare) SHRIT. P. New Delhi Central Water Commission. LAKHERA(Alternafe) CHAIRMAN-CUM-MANAGING DIRECXOR Natioilal Buildings Construction Corporation. New Delhi SHRIN. BALI (Alternare) SHRID.B. GU~TA SHRIJ. Jammu & Kashmir Indian Institute of Remote Sensing. New Delhi SHRIM. Simla Structural Engineering Research Centre. KUMAR(Ajternate) CHIEFENGINEER (DAM DESIGN) Supnx ENGINEER (TEHRIDAM DESIGNCIRCLE) (Alted Uttar-Pradesh Irrigation Design Organization. D. Chennai SHRI N. K. DASGWTA (Alrernure) Geological Survey of India. MEHROTRA SHRIN. New Delhi CHIEFENGINEER (ROADS) SWTDG ENGINEER (ROADS)(AIfernute) DIRECTOR. Roorkee SHRIP. K. Dehra Dun DR U. N. S. New Delhi SHRIB. C. B. SLJRESH Housing & Urban Development Members SHRID. Lucknow Central Soil & Material Research Station. BIS SHRISANIAYPANT Deputy Director (Civ Engg). U. BABRAR(Alternate) DR N. BIS (Ex-@cio Member) Director (Civ Engg) Member Secreturies SHRI T. Hill Area Development Board. SURVEYOR OF WORKS-I (NZ) (Alternate) SHRI V. VENKATACI~ALAM SHRIS. VIRDHI SHRI VINOD KU~JAR. Dehra Dun Director General. S. New Delhi Wadia Institute of Himalayan Geology. TIWARI SHRIK.P. K. BIS New Delhi . NARAYANAN Joint Director (Civ Engg).IS 14458 (Part 1) : 1998 ( Continufrrwi puge 7 ) Suproc SURVEYOR OFWORKS (NZ) Representing Central Public Works Department. P. SINOH(Alternate) SHRIS. New Delhi Corporation (HUDCO). a standard along with amendments is reaffirmed when such review indicates that no changes are needed. New Delhi. type or grade designations. 1986 to promote and quality certification of goods Copyright BIS has the copyright of all its publications. of Indian marking Standurds Act.337 337 86 26. of necessary details. PUNE.323 33 75. FARIDABAD.8327892 : AHMADABAD.T. This Indian Standard has been developed Amendments Amend CED from Dot : No. No part of these publications may oe reproduced in any form without the prior permission in writing of BIS. 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