AASHTO R 45-2013 Standard Practice for Installing Monitoring and Processing Data of the Traveling Type Slope Inclinometer.pdf

1、Standard Practice for Installing, Monitoring, and Processing Data of the Traveling Type Slope Inclinometer AASHTO Designation: R 45-13 American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-1b R 45-1 AASHTO Standard Pract

2、ice for Installing, Monitoring, and Processing Data of the Traveling Type Slope Inclinometer AASHTO Designation: R 45-13 1. SCOPE 1.1. This practice provides instructions for installation, monitoring, and data reduction for the traveling type slope inclinometer for use with guide casing. A slope inc

3、linometer is a precision instrument that measures lateral displacement of a guide casing resulting from the movement of earth, concrete, or other masses. This type of instrument can be used to detect and monitor movements in earth- and rock-fill dams, highway embankments and foundations, excavation

4、slopes, sheet pile bulkheads, concrete retaining walls, and other structures. Because the instrument is waterproof, it can be used on projects where normal measurements would not be feasible, such as the displacement of the lower portion of a pipe pile. The data, which are well suited for computer r

5、eduction, can be used to interpret shear zones in landslide areas and as a basis for predicting impending shear failures or structural failures based on the amount and rate of lateral deformation occurring. 1.2. The practice is divided into the following parts: 1.2.1. Part I, Installing Slope Inclin

6、ometer Guide Casing; 1.2.2. Part II, Monitoring Slope Inclinometer Guide Casing; and 1.2.3. Part III, Data Computations and Analysis. 1.3. The values stated in SI units are to be regarded as the standard. PART IINSTALLING SLOPE INCLINOMETER GUIDE CASING 2. APPARATUS 2.1. Drilling Equipment: 2.1.1. D

7、rill rig capable of drilling a hole with diameter large enough to accommodate the particular size slope inclinometer casing used and allow for adequate backfilling. The depth of the hole needed varies with the particular installation, locale, and/or discretion of the engineer. Normally, a drill rig

8、capable of drilling a 203-mm (8-in.) diameter hole to the desired installation depth may be used. A smaller drill rig may be used for shallow depth installations. 2.2. Guide Casing: 2014 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a v

9、iolation of applicable law.TS-1b R 45-2 AASHTO 2.2.1. Guide casing, usually round extruded plastic, with four equally spaced longitudinal grooves on the inside of the casing compatible with the particular torpedo sensor used. However, some casing may not be grooved because the torpedo sensor maintai

10、ns proper orientation by use of locking metal orientation rods. Some inclinometers may be used in square steel casing with the torpedo sensor guide wheels tracking in opposite corners of the casing. The casing comes in assorted diameters and may come in any convenient length, such as 1.52- or 3.05-m

11、 (5- or 10-ft) sections. 2.3. Couplings: 2.3.1. The couplings may be extruded plastic with four equally spaced grooves and usually come in 152-mm (6-in.) lengths. In cases where settlement is expected, longer couplings may be used to join the sections of casing. The resulting gap between casing sect

12、ions allows the casing to telescope together as compression of the surrounding materials occurs. Alternately, a coupling mechanism may be included as part of the guide casing. 2.4. Installation Tools: 2.4.1. Inclinometer guide casing installation tools specified by the manufacturer, normally consist

13、ing of hacksaw, casing clamp, casing anchor (recommended), tape measure, and a device for marking casing grooves such as a felt tip marker or file. A special wheel groove alignment tool, duct or masking tape, and solvent cement may be needed for plastic casing. A vibrator and/or grout pump may be us

14、ed for backfill compaction and placement if necessary. 2.5. Plugs: 2.5.1. Plugs compatible with the particular guide casing are used for protecting the top and bottom of the casing from mud and debris. A conical plug may be used to ease insertion of the casing into a rough-sided hole. 2.6. Protectiv

15、e Device (Optional): 2.6.1. Hole cover or other protective device to minimize vandalism and large enough 152 mm (6 in.) to allow the cable clamp-guide wheel assembly to be installed on top of the casing. A metal pipe with either a threaded cap or hinged lid with hasp and lock may be used. For protec

16、tion from impacts by construction traffic, bollards or barriers may be installed. 3. DRILLING AND HOLE PREPARATION 3.1. The size of the drill hole should be large enough to accommodate the particular size casing used and depends on the particular installation, locale, materials encountered, depth of

17、 the hole, available backfill materials, or the discretion of the engineer. Larger holes facilitate backfilling. Minimum diameter may be only sufficient to accommodate the casing used. This is applicable in cases where the material may close quickly. Normally, the drill hole may be approximately two

18、 times the outside diameter of the casing or a minimum of 127 to 152 mm (5 to 6 in.). The hole should be as vertical as possible (vertical inclination should be less than 3 degrees), and drilled several meters (at least 3 m, or as directed by the engineer) into stable material below or beyond the an

19、ticipated zone of movement. Usually, the borehole should extend into rock or soil to achieve sufficient rigidity to provide the fixity of the inclinometer. The bottom 3 m (or as directed by the engineer) of the inclinometer casing should be embedded below the lowest possible failure plane and should

20、 extend into hard or very dense material to assure that the future readings do not show any movement at the bottom of the inclinometer casing. 3.2. The hole usually should be cleaned by flushing with water or blowing compressed air before attempting to install the inclinometer casing. Depending on t

21、he installation, sometimes it is 2014 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1b R 45-3 AASHTO necessary to leave drilling mud (if it is used) in the borehole to control caving, thereby allowing pr

22、oper backfill. 3.3. Any means of accomplishing a boring is satisfactory as long as it is suitable to the engineer and conditions at the site. If the ground is firm and the hole will remain open without steel casing, then either a dry hole (drilled with a continuous flight auger) or a water-filled ho

23、le (drilled with a chopping bit or a rotary bit and using water to flush out the cuttings) is satisfactory. 3.3.1. Hollow stem augers may be used with success because the augers can be pulled after installation of the slope inclinometer casing. If the hole is likely to squeeze in because of soft soi

24、ls or cave because of sand, drilling mud may be used and left in the hole upon completion of the boring. 3.3.2. If drilling mud is used, some difficulty may be encountered in making the inclinometer casing go down completely in the hole, but this may be remedied by filling the casing with water or o

25、ther physical means. 3.4. Steel or any other type of casing may be used if justified to prevent the hole from caving. Usually, steel flush joint drill casing may be used. The steel casing should be a diameter large enough to allow backfill material to be placed in the annular space between the steel

26、 casing and the outside of the slope inclinometer casing. The backfill material then can be shoveled or poured in small amounts while at the same time pulling the steel casing in small increments. Care should be taken so that the backfill material does not lock the steel casing to the slope inclinom

27、eter casing. In extremely difficult cases, steel casing may be left in place upon completion of the boring. However, the use of steel casing tends to reduce the precision of the measurements within the zone of movement. Care should be taken to maintain proper orientation of the slope inclinometer ca

28、sing while backfilling. 3.5. Inclinometers may be installed in structures and retaining walls to monitor performance and stability. Casing may be incorporated into the structure design or installed after construction by drilling or coring. To prevent damage, casing designed for installation during c

29、onstruction may be placed inside a construction casing, which is grouted into place. 4. INCLINOMETER CASING INSTALLATION 4.1. Any type of soil inclinometer casing may be used as long as it meets the slope inclinometer manufacturers requirements and is compatible with the particular sensor torpedo us

30、ed. Usually, plastic casing is used in most installations; however, steel or other types of casing may be used under certain conditions such as embedment in concrete structures. Orientation of the casing tracking grooves should be properly maintained throughout installation. The grooves should be or

31、iented parallel and perpendicular to the anticipated direction of movement or at the discretion of the engineer. However, groove orientation of the casings in different holes should be consistent to avoid confusion. The installation may be expedited if the casing is preassembled and coupled together

32、 in units of 3.05 to 7.62 m (10 to 25 ft) each. The following is a brief explanation of the installation techniques for typical casing; reference should be made to the manufacturers instruction manual for a more detailed explanation. Refer to Figure 1. 2014 by the American Association of State Highw

33、ay and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1b R 45-4 AASHTO Note: 1.52 m = 5 ft 3.05 m = 10 ft Figure 1Typical Assembly of Slope Inclinometer Casing 4.2. Casing: 4.2.1. Attach a plug to the bottom section of casing by using solvent cement, po

34、p rivets, self-locking devices provided with the casing, or other manufactured supplied coupling. If required, attach a plastic coupling to the top end of casing with solvent cement, pop rivets, self-locking devices provided with the casing, or other supplied coupling. 4.2.2. Lower the first section

35、 of casing into the boring with the plug on the lower end and the coupling attached to the top. A casing clamp should be attached approximately 0.3 to 0.6 m (1 to 2 ft) from the top of the casing. 2014 by the American Association of State Highway and Transportation Officials.All rights reserved. Dup

36、lication is a violation of applicable law.TS-1b R 45-5 AASHTO 4.2.3. Each end of the casing may be marked with a scribe line or felt tip marker to prevent rivets, if used, from being placed in the instrument tracking grooves. Either solvent cement compatible with the casing, self-locking devices, po

37、p rivets, and/or other manufactured supplied coupling may be used to join the casing and couplings. Any combination of these methods may be used for extremely deep installations. 4.2.4. The two sections are carefully attached together, thus lining up the tracking grooves. The casing ends should be b

38、utted together. The two sections may be attached with pop rivets, solvent cement, self-locking devices, and/or other manufactured supplied coupling. Casing clamps may be used to prevent the casing from falling into the hole. Lower and attach another section of casing and repeat the previous procedur

39、e until the casing rests on the bottom of the hole. Cut off any excess casing to a desirable height with a hacksaw. The predetermined orientation of the instrument tracking grooves should be properly maintained. Installation procedures are the same for telescoping couplings, except special fasteners

40、 are usually used to automatically align the grooves. If telescoping couplings are used, the casing should not be allowed to rest on the bottom of the borehole, where the weight of the casing would cause the sections to telescope together. Pop rivets or any similar products may be used to prevent th

41、e telescoping couplings from collapsing during installation. Pop rivets should not be placed directly in the alignment of the casings grove. One to two aluminum rivets are recommended (or as directed by the engineer) to prevent the casing from collapsing. The rivets shall be installed about 1/2in. f

42、rom the edge of the section body (with telescoping sleeves extended to accommodate settlement). A typical telescoping coupler allows 6 in. of compression or extension. 4.3. The couplings of the casing may or may not be watertight. If the boring is filled with drilling mud, the mud may enter the casi

43、ng as it is installed. Likewise, the injection of grout to fill the annular space around the casing may result in grout entering the casing. 4.3.1. In such instances, the casing should be flushed with clean water before the grout has hardened. A stiff brush may also be lowered down the casing during

44、 washing to ensure that the longitudinal grooves are clean. Inflow of mud or grout may be lessened by waxing, gluing, or taping all joints. 4.4. If sand or gravel is used as the backfill material and groundwater measurements are desired from the installation, small holes or slots may be drilled into

45、 the bottom section of inclinometer casing. 5. BACKFILLING THE INCLINOMETER CASING 5.1. The quality and extent of backfilling the slope inclinometer casing depends on the particular installation, groundwater conditions, type of backfill materials, or discretion of the engineer. Best results are obta

46、ined if care is taken in backfilling to eliminate any voids, bridging, or settlement in the backfill material. An air-impelled or other type vibrator may be used to alleviate bridging. Backfill materials should be of similar shear strength to the in situ materials. 5.2. A cap may be placed over the

47、top end of the casing prior to backfilling to prevent any backfill materials falling into the casing. 5.3. Dry Sand: 5.3.1. Dry sand may be used when the boring is dry, relatively shallow, and of a fairly small diameter, about 127 to 203 mm (5 to 8 in.). The sand should be clean, dry, and of uniform

48、 size, if possible. Standard Ottawa sand is ideal; washed concrete sand is acceptable. The sand may be densified by vibrations, shoveled, or poured slowly through a wire screen to eliminate bridging. Sometimes, sand may settle later and produce both vertical and horizontal deformations of the casing

49、, which are not the result of ground movements. Water may be used to backfill the hole to eliminate any voids or bridging and densify the sand. 2014 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1b R 45-6 AASHTO 5.4. Pea Gravel: 5.4.1. Any gravel suitable to the engineer may be used. Pea gravel 9.5 mm (or 3/8in.) or No. 9 crushed limestone chips are examples. The gravel may be shoveled slowly in small increments to eliminate any bridging that might occur. Gravel may be used in de