Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Summary of Issues from TUCWG Meeting JOSHUA L. MERRITT Merritt CASES, Inc. Redlands, California SUMMARY: The meeting of the Tunneling and Underground Construction Working Group (TUCWG), which was held on l5 and l6 October at the Defense Nuclear Agency, was a precursor to look at some of the more critical problems and issues. Construction and siting were the major issues discussed. The typical reaction voiced by most members of the group was that if we were re- quired to, we could proceed now with construction of a facility at approximately 2,600 feet in depth in a sandstone, for example. The major considerations confronting us in that case would be the following: â¢ Schedule â¢ Cost â¢ Other key issues to be expected and how the may best be resolved by a program beginning now. A feeling common among the members was that "digout," or egress, as it has been called, will have to occur at least in concept; we have to be prepared to egress af- ter an attack. The urgent needs and recommendations discussed included the following: â¢ Management organization â¢ Adequate staffing â¢ Definition of promising sites â¢ Configuration compatible with chosen site. A small group had studied earlier the possibility of using underground space al- ready in existence. The results of that study are included in this presentation. It was not an exhaustive study, but just a preliminary look at what may be available and useful. During the meeting of the Siting Subgroup, the issue of digout, or egress, was discussed at length. A major outcome of this subgroup meeting was a preliminary ba- sis for applying decision analysis techniques to the siting problem. Several siting concept alternatives were discussed: mesas, ridges, and plains. Concepts were solicited for generally desirable site characteristics in terms of ver- tical relief, talus slopes, and other conditions. Some possible schemes for solving the egress problem are discussed in this pre- sentation, including methods for vertical, horizontal, and inclined egress. In summary, it is important to point out that the problem of egress is not by any means solved. Inputs in this area are urgently needed. l22
l23 We have given to your chairman, Dr. Cording, about 20 copies of the re- ports that were received as a result of the meeting on October l5 and l6. They will be available to you for consideration in your further delibera- tions. The meeting on October l5 and l6 was merely a precursor to begin to look at some of the more critical problems and issues, and I would em- phasize at the outset that it was only a two-day meeting. The first three-quarters of the first day was spent on construction. The rest of that day and the following day were spent on siting issues. Obviously, it has been a very brief consideration and certainly deserves a lot more consideration. I should finally emphasize that the reports that you will receive, the 20 copies or so that we have, are listed as draft reports of the in- dividual members of the working groups. Please look at them as drafts. Again, an awful lot of work needs yet to be done. I would emphasize, again, that this meeting is unclassified. Our meeting on October l5 and l6 was also unclassified, so that there is no classified information in any of those reports which will be available for your perusal. Figure l lists the group that convened on October l5. The working group members are listed at the top, and there were a number of other attendees. The meeting was held at the Defense Nuclear Agency. Figure 2 lists some of the meeting's conclusions. Perhaps I was a little too strong in calling this a "consensus." There are perhaps some items of consensus here. There are probably some items that might be further debated; I apologize for using the word "consensus." I think, however, it is important to note the typical reaction. I merely quoted Al Mathews in the typical reaction, but this reaction was also voiced by the other members that have provided a report. The reaction is that if we were required to proceed with the construction of a facility at, let us say, 2,600 feet in depth in (for example) a sandstone, there is no question that we could go do it. As Colonel Rule has indicated, the big issues are how quickly can it be done, what is the cost of doing it, and what are some of the other issues that might be resolved in the process? Another item that was common among all of the written reports is that digout, or egress as it has been called here several times today, is something that needs to have a great deal of work, and as one of the persons on the committee has indicated, egress, as a matter of policy, will have to occur at least in concept. We have to be prepared to egress after an attack. Some of the "urgent needs and recommendations" (Figure 3) are my paraphrases of the various reports that were received following the three- quarter day meeting. We touched on one of the questions that has been raised before, and that is the management organization and the adequate staffing of this very important program of tremendous magnitude. Other questions are also shown in the figure, and the final one is to define the properties of promising sites and then configure, or optimize a con- figuration, to be compatible with that site. In response to a request of the Under Secretary of Defense for Re- search and Development back in early August, we convened a small group to look at what underground space existed and what the possible use of
l24 that space might be. Figure 4 shows some of the highlights of the con- clusion. Some 80 mineral mines were identified from a preliminary inven- tory, and 35 of them had overburdens greater than l,500 ft. Of that 35, 26 are currently operating, and there might be a problem of acquisition or perhaps, instead of acquisition, parallel use of the space. The four operating mines with vertical egress are indicated. The "8" x l0'" not- ed in the figure is the typical size of the opening; the l,600 or 3,l60 feet is the depth. Of the remaining nine existing openings, seven non- operating mines are flooded, and the actual conditions of the underground space there are unknown. Two nonoperating mines are dry, as indicated. The group looking at this problemâover a brief period of only two or three daysâidentified the fact that, of course, several other govern- ment agencies (one highlighted in the figure, the Nuclear Regulatory Com- mission) have investigated existing space for possible use for nuclear waste disposal. A third item from that particular study was that there are abandoned railroad tunnels that have the characteristics indicated; four in particular might be attractive in that they are in government- controlled public areas. The final area that was identified was limestone mines. There was no effort to look at natural limestone caves within this very abbreviated study, but there are limestone mines in existence. There are a large num- ber with numerous sizes of openings and naturally dry conditions. They may be weak, due to the room-and-pillar excavation that was used in these limestone and dolomite areas. The recommended additional work to develop these data is indicated. I would emphasize again that this was primarily three people working for two to three days; it is certainly not an exhaustive study by any means. It was merely the first cut at what might be available and what might be useful. There is a potential for a lot more consideration in that area. The Siting Subgroup of the Tunneling and Underground Construction Working Group (Figure 5) met on Thursday afternoon and then continued on Friday, October l6. The subgroup members are as indicated, and the other attendees of the October l6 meeting are listed at the bottom. Obviously I lost my courage in calling the material in Figure 6 a consensus at this point. Again, the items of digout were of paramount concern, and the figure lists some of the things that Ron Heuer had to say about digout. I would emphasize that he indicates that obviously if we can go through soil or alluvium we certainly simplify one of the problems; there are machines that might go through that. At the same time, of course, because we would have to carry along continuous support for such a medium, we do not solve the entire problem by going through alluvium. Jim Gould had an important item for consideration, particularly in view of the so-called "SUMS" involving the placing of missiles on small submarines which came up as part of the multiple protective shelter (MPS) considerations (Figure 7). He indicated that we might want to look at some of the Continental Shelf areas (possibly the United States terri- tories under the Great Lakes could be looked at as potential siting areas as well). Although at the same time I must note that penetrating devices
l25 can more readily go into water than they can into rock, there may be some other advantages of locating off the Continental Shelf or under the Great Lakes. Finally, from the Siting Subgroup (Figure 8), I am remiss in not identifying the source of this information: it was suggested by Gene Waggoner as a potential means of siting decision analysis techniques in a simplified way. In his report he gives a more complete decision analy- sis approach to looking at siting. He noted in his letter transmitting this material that Item 2 may immediately throw out a site if it is de- termined that the particular characteristics of that site make its abil- ity to survive attack very doubtful. Even though one might go through a weighing of important parameters, one might single out an item, such as survivability. Since survivability is the name of the game regardless of how the site turns out otherwise, obviously if it cannot survive it would be eliminated from further consideration. Now, to move to a different subject. The one perhaps that we are here for is to look at siting concept alternatives. I had the staff put together a complicated cartoon of things that you might wish to consider. We have heard a lot about mesas because mesas provide horizontal egress into the area both for construction as well as possibly for mining out after an attack. Figure 9 is intended merely to flag the fact that there are mesas. One example is Grand Mesa, Colorado. We have indicated in the figure that we wish to stand off somewhere between 2,000 and 3,500 feet, depending upon the type of rock that we might be in as well as the trade-offs of hardness with depth. We recognize that there may be sev- eral levels of talus slopes that might exist against the mesa, not only at different geographical locations, but even at the same mesa. Configuration was intentionally left as a blob in Figure 9 because it could be vertical, it could be horizontal, or it could be a hybrid of horizontal and vertical. It could also involve a situation where we might have certain assets at a greater depth than other assets. Depend- ing on the criticality and required hardness of those assets, we might want to put them at a greater depth and thereby provide them greater survivability. Figure 9 gives one example of a ridge site: either side of Forty- Mile Canyon in Nevada. There is a fairly significant vertical relief there. There are many others throughout the country that might be pos- sibilities; again, a blob is indicated for the configuration. We might have to go deeper into a ridge to make sure that we get our 2,000 to 3,500 feet of standoff distance between the nearest point on the surface and the facility, so that it may actually be, say, 4,000 feet below the local ridgeline. Dotted lines are used to indicate the possibility of various levels of talus slopes and alluvial fans adjacent to such a ridge. The third possibility, of course, is to go into a plain, such as the basalt at the Columbia River Basin. We have indicated Washington near Fairchild Air Force Base, but, of course, the basalt extends further. As shown in Colonel Rule's earlier chart, it is also in Oregon. If located under a plain, we would have to have vertical egress systems as well as vertical shafts in order to mount the construction. Finally, we solicit
l26 your ideas or your concepts for what is a desirable site in terms of ver- tical relief, talus slopes, and other conditions. Finally, I have a very complicated chart (Figure l0) that was put together just as we were rushing out. I should start with the punch line of "your concept": we really want your concept and ideas; what we are merely trying to highlight here are some off-the-top-of-the-head kinds of things that one might consider, and certainly by no means is it exhaustive. It suggests some thoughts that one might want to consider as you go into your deliberations on possible schemes for solving the egress problem. First, we started with vertical egress, where we assumed that we mine out after an attack using a raise climber and using the main tunnel for muck disposal. The main tunnel for muck disposal may not be the most attractive thing, but that perhaps is a point of departure. I should have mentioned the dashed line on the figure. The dashed line is to indicate that in this particular case, of course, we could be under a plain where we do not have any major vertical relief and would have to go into a vertical egress system. The missile would have to carry with it everything that is required to take it out of the hole, assemble itself, get its initial alignment, and take off. There would have to be some sort of a chamber back into the plain or out into the plain that allows you to make the transition of that 70- to l00-foot missile. As Figure l0 shows, in cartoon form, we could partially or complete- ly predig the tunnel and backfill it with several alternative materials. The plug at the top would probably have to be significantly deeper than shown. As Dr. Linger has pointed out, if they actually knew the location of the egress point (we certainly must assume that they would know), it would then become a target. Consequently, the crater would come to per- haps a 300-foot depth and the plug shown might have to be more than 300 feet deep to ensure that it avoided the crater. With some of the mate- rials with which one might backfill a predug egress way, you would still have to use a raise climber or a raise borer in order to get rid of the material. Another possibility would be to use preset charges, not only to break up the plug at the top and possibly the bottom, but also the back- fill, to break up the natural arches that are going to form as we try to have 2,000 feet of muck fall through the shaft; in this case, of course, we would not need a raise climber. I would hasten to add, however, due to electromagnetic pulse (BMP) effects'âequivalent to the worst lightning storm you could imagine increased manyfoldâprotecting the charges from that sort of electrical transient may be difficult, but certainly it is something that could be investigated. Also, there is the possibility of having a predug muck pocket at the base; in that case, of course, one could eliminate any need for providing conveying systems to get rid of the muck as it falls. Finally, of course, is a possibility of using an offset vertical egress system. Another consideration for egress is proliferation. Proliferation, however, is not very attractive because, as indicated this morning, we are talking about thousands of potential warheads to attack the triad;
l27 thus we would need thousands of such openings, which is not cost-effec- tive. Additionally, we could have a defense overlay to protect some openings. Now, let me very quickly walk through the same sort of thing for inclined egress (Figure ll). Inclined egress would require a slope, of course, that would depend on the talus configuration. It does not appear as attractive to go out on the incline if you have to go all the way to the upper surface. The angle is a variable depending on the site, as well as perhaps some of the mechanization. Recognizing this, we can dis- cuss the same sorts of possibilities as we did for vertical egress. I shall not comment further except to point out that one needs, of course, some sort of a door to assure that the muck goes into the muck pocket and then drop the door in order to get access to take the missile out. For inclined egress, I would emphasize another possibility. If we can prove that we can get preset charges to survive EMP and other near surface effects, we could have preset charges on the slope providing there was no major talus slope. Preset charges could remove the top of the slope and other charges could remove the final plug such that we would get access passively to the surface. Finally, Figure l2 shows horizontal or nearly horizontal egress. The cross-hatching which now appears on the talus slope indicates that the final opening would have to come out on a clean surface, not through the talus, although one could certainly come up with a scheme with a shield and full lining to go through the talus. We shall merely walk through the several possibilities for near horizontal egress. In this case, blast doors might be an attractive addition, and I would mention that the Defense Nuclear Agency for years has used first a structure called a tunnel and pipe seal (TAPS) at the Nevada Test Site, which is designed for rather impressive overpressures and temperatures. More recently, they have used DACS (DNA Auxiliary Closure System) and variations of the DACS, which is a very rapidly closing blast door that can take very high temperatures and pressures. For near horizontal egress, we would excavate probably with a tunnel boring machine (TBM) or some variant of a TBM. In summary, I would come back to my initial point: the three com- plicated figures (Figures l0, ll, and l2) merely lead up to the fact that the problem has not been solved by any means. We need your inputs very urgently in this area.
l28 at LU co âI uj a uj < a < uj I <_> u <r â u. <z < at co z uj v> at z z uj o a < at ^ - Sot U. Ul o o co z > â¢> UJ ~J CO CO Z UJ ^x â </) _) UJ > UJ CC -5 uj . < Q i/5 3: X co z O 3 < - - â R J UJ -> Â£ < UJ UJ X UJ a.a 19 UJ at at â¢>UJ ujaa -UJ aou ae QU. at< 0 UJ Â§ z o O SE iâ tâ l_> UJ i* OO iât t_> i-H a ex LA S UJ ii 13 o e^ UJ > _J â¢ X O Q z ae u * CO V) UJ uj a. CO < O h- O z z t- ~ 3 01 CO LU Z CO o < u u EQ , EREA, EEES , EE0 E_SE, , , EEE, EESEE, 3 , EEE_, EEE, S ,EESKE, EENNES , EEEE, EEEE NE . WESNRNE, EE o _! R ae UJ UJ UL 0 | ~ Z â â¢Â» CO at z o ae o co LU ae 3 Â£ cr ae ae ae co o a _l u 3 - (- < >e _l a. -I uj aS Ml ONA - i at UJ â¢> -J Â£ U) Z z cr u_ * co aa ae o z â¢> UJ CO LU Z z 3 aS o o UJ a ae â¢> â z o i- â¢ < i- a _l . < a. â¢jo. a - X UJ < oc z o < LU t- - Â£ O _l Â£ f a ae ESSS UJ CO O I- Â£ ae aa ui ae en uj ^ R CO UJ ae z -i LU z UJ o 3 UJ at ^ ae * x u o ae - u at _l ui i < ae UJ O ae UJ (A < ae UJ (A O CA ae -I Z Â£ a i a â¢> at UJ X u. U < < â¢Â« >N. co ae a 3 LU x co â¢> 3 â¢Â» a o >â¢ X X LU UJ CO z o > UJ Z h- UJ Z u7 UJ â _) -. a > J > UJ UJ < - a u. - u. o z t- -j CO CO â¢ LU Â» UJ Â§551 O T Â£ T ae < x UJ ae x u. _l CO UJ IT Q X Â« UJ Â£ 0 U a: CJ
l29 CONSENSUS FIRST MEETING OF TUNNELING AND UNDERGROUND CONSTRUCTION WORKING GROUP 15 OCTOBER 1981 TYPICAL REACTION (QUOTE FROM A. A. MATMtWS): EXISTING TECHNOLOGY IS ADEQUATE TO ASSURE THE SATISFACTORY COMPLETION OF ALL UNDERGROUND CONSTRUCTION NECESSARY FOR THE COMMISSIONING OF AN ACCEPTABLE DEEP BASING SYSTEM IN A SUITABLE GEOLOGIC SETTING. HIGHLY PROMISING AREAS FOR IMPROVEMENT OF TECHNOLOGY (QUOTE FROM A. A. MATHEWS): CONTINUOUS CONCRETE LINING PLACEMENT BEHIND TBM AUTOMATIC APPLICATION OF SHOTCRETE VERY HIGH SPEED RAIL HAULAGE HIGH PRESSURE, PRE'COOLED VENTILATION AIR FRANGIBLE BACKING FOR SUPPORT ELEMENTS DIG-OUT, ESPECIALLY THROUGH RUBBLE, NEEDS DEVELOPMENT/DEMONSTRATION, CONSIDER AS EXAMPLES (QUOTE FROM R. E. HEUER): DIG OUT THROUGH CRATER RUBBLE AT RATES OF 100 FT/DAY MAY BE POSSIBLE IF: I. DONE AT SLOPES OF LESS THAN 20? II. CRATER RUBBLE IS SOIL OR LOW STRENGTH ROCK III. CRATER RUBBLE IS ABOVE THE WATER TABLE CURRENTLY AVAILABLE TUNNEL BORING MACHINES (SUCH AS THE LOVAT MACHINE, FULL SHIELDED WITH DRAG BIT CUTTERS) AND TUNNEL LINING SYSTEMS (PRECAST CONCRETE OR STEEL RIBS WITH HOOD LAGGING) ARE LIKELY TO PROVE ADEQUATE FOR THESE CONDITIONS. FIGURE 2 URGENT NEEDS/RECOMMENDATIONS FIRST MEETING OF TUNNELING AND UNDERGROUND CONSTRUCTION WORKING GROUP 15 OCTOBER 1981 PROCEED WITH HIGHLY PROMISING AREAS FOR IMPROVEMENTS IN TECHNOLOGY ESTABLISH A MANAGEMENT ORGANIZATION AND PROVIDE ADEQUATE STAFF NOW STRUCTURE INNOVATIVE APPROACHES TO DEFINITION OF WORK AREAS AND CONTRACTING DEFINE PROPERTIES OF PROMISING SITES AND CONFIGURE (OPTIMIZE) A SPECIFIC FACILITY FOR SITE FIGURE 3
l30 EXISTING UNDERGROUND SPACE FOR MISSILE OPERATIONS PRELIMINARY INVENTORY OF 80 MINERAL MINES OF WHICH: 35 HAVE OVERBURDEN OF GREATER THAN 1500 FT. 26 OF THESE ARE OPERATING: PROBLEM WITH ACQUISION? 1 OPERATING MINES ARE DRY: GREEN RIVER (WYOMING) - 8' X 10' AT 1600' SAN MANUAL (ARIZONA) - 10' X 12' AT 3160' SAFFORD (ARIZONA) - UNKNOWN AT 2300' VERTICAL ACCESS WHITE PINE (MICHIGAN) - 8' x 11' AT 1500' 7 NON-OPERATING MINES ARE FLOODED 2 NON-OPERATING MINES ARE DRY: LAKE SHORE (ARIZONA) - 8' X 12' AT 1800' TUNGSTEN QUEEN (NORTH CAROLINA) - 10' X 12' AT 1700' INVENTORIES BY OTHER GOVERNMENT AGENCIES: NUCLEAR REGULATORY COMMISSION INVESTIGATION FOR NUCLEAR WASTE DISPOSAL ABANDONED RAILROAD TUNNELS: HORIZONTAL ACCESS EXISTING TUNNEL SUPPORT 1 LOCATED WITHIN GOVERNMENT CONTROLLED PUBLIC AREAS: CASCADE TUNNEL (WASHINGTON) ALPINE TUNNEL (COLORADO) HAGERMAN TUNNEL (COLORADO) ATLANTIC-PACIFIC TUNNEL (COLORADO) LIMESTONE MINES: LARGE NUMBER AND NUMEROUS SIZES OF OPENINGS WITH NATURALLY DRY CONDITIONS WEAK DUE TO ROOM AND PILLAR TYPE EXCAVATION METHODS RECOMMENDED ADDITIONAL WORK TO DEVELOP THESE DATA FURTHER: EVALUATE HARDNESS OF OPENINGS INVESTIGATE ABANDONED RAILROAD TUNNELS INVESTIGATE WORK DONE BY OTHER AGENCIES FIGURE 4
l3l Q. EA NERSRNESE R PEEPENBERN, ., RNA LAERE, REL RE_, BMO/_N CEARR SADLE, RRCE~MX/RE_S J. SEOR_, RESRRE/S&ENF (O&SS EEE, E, B. SE_PHE_, RRCE-MX/REEC ROSEER, BR_ENN (RBSEVER) O a: z o; in UJ <^ UJ a. _ i â¢ Q X O <-O i i Q â¢ O O O ce LU -3 ce z z < - x c_ 0 ~3 U < 0 â¢=> t-^i 'ââ i en CJ z h- - (- Â£ sE _l LU O = LU UJ -I X -1 O 1 â â¢a (9 1 00 Â»-H LU ^ z CQ f*"E OO O z CO â i O> a o UJ h- C/O l_) UJ iâ Â«J O as UJ i CLS ^ V) 3 ^^ 1 | \ tâ u (9 CO _* Â«H o CO ae X Z < h- 3 z? o Iâ O 3 < Z 1- u â¢â ex iâ % z 1â Q â -^ 00 <^ t > ^ ae o _l ce Z ^ ex: o Q UJ 3 â¢Â« ce 0 ae LU OO X CO UJ GO O UJ LU ca U3 Or UJ O z x s: ^~ Z â¢ X ~^ iâ 1 UJ % 23 o ae 0 u o =3 ca Of y ^ UJ z ce ca x: UJ z ce t- 0) o LU X -> o â¢Â« LU tâ o o ^^ y en Q tâ ce o â¢â¢ ae X ^ CO <= O. _ â U a. LU z ce M UJ u_ s: o â ce â¢ â¢ UJ u. O (9 < LU -J UJ u aa CO * 2: OS OB X JZ UJ UJ j u _j 'O â¢ z - <; â¢ z z a â UJ 1 _J a. R LU _J UJ LU 1â x ce ^^ CQ _j Z 0 o ^ H- LU Â§ =3 OO < UJ ae* Â§ o 3 UJ z Q. ~t O UJ ae 3E 0 Z hâ X ae O "1 UI ce 3 â¢> â¢ â¢ ce _l ce X ce ce m t- _l i- 0 â¢> LU X Q X UJ I J , -1 0 UJ - (J -X .3 _ ce a ce _i Z tâ < 5 ce co UJ ce ^ â¢Â« ce co o o U) ^ LU Z - z o LU <Â£ ca x z z x < a. ~3 UJ ae 1 ,: 1 o g . a: LU CO u 3 ce X iâ i t- LU â¢ -J Q. X u_ o -J _I -3 z â¢*
l32 QUOTE FROM R. HEUER DIG OUT. SELECT SITE SO THAT POTENTIAL CRATER RUBBLE TO BE PENETRATED DURING DIG OUT IS: I. THROUGH LOW STRENGTH ROCK (2000 PSI OR LESS) OR SOIL (SUCH AS DESERT ALLUVIUM) . I I. ABOVE WATER TABLE (WANT LOOSE PERMEABLE, RUBBLE TO BE DRY, NOT FULL OF WATER). III. LOCATED TO PERMIT DIG OUT AT RELATIVELY FLAT INCLINATION: (A) PREFERABLY LESS THAN 3Z, AMENABLE TO RAIL HAULAGE (B) POSSIBLY UP TO 201, USING RUBBER TIRED VEHICLES WITH PROBABLE RESULTING SLOWER ADVANCE, HIGHER ENERGY REQUIREMENTS, GREATER PROBLEMS WITH POLLUTION OF BASE ATMOSPHERE, ETC. IV. LOCATED TO PERMIT DIGOUT INTO STEEP SLOPE (A) LESS RUBBLE ACCUMULATION. (B) GREATER LIKELIHOOD OF FAVORABLE GROUNDWATER TABLE. (C) REDUCED DIG OUT DISTANCE. QUOTE FROM A. A. MATHEWS: SITING NEEDS. DESIRABLE GEOLOGIC, TOPOGRAPHIC AND GEOGRAPHIC CRITERIA SHOULD BE IDENTIFIED AND ALL POSSIBLE SITES MEETING THE MINIMUM STANDARDS SHOULD BE LOCATED. THESE SELECTIONS CAN THEN BE CLASSIFIED IN ORDER OF PREFERENCE. FIGURE 6 QUOTE FROM T. McCUSKER: EFFECT OF GROUND TYPE: PRODUCTIVITY ~ POTENTIAL RANKING: TUFF, LIMESTONE (MASSIVE, NO GYPSUM), SCHIST/GNEISS, BASALT, GRANITE, METAVOLCANICS WITH HIGH HORNBLENDE CONTENT BEHAVIOR UNDER BLAST EFFECTS SHOCK ISOLATION CONSTRUCTION METHODS QUOTE FROM J. GOULD: A SCHEME THAT COULD BE CONSIDERED IS BASING ON THE CONTINENTAL SHELF WITH APPROACH TUNNELS FROM LAND ACCESS POINTS. COASTAL PLAIN SEDIMENTS ALONG THE MID-ATLANTIC BETWEEN THE HUDSON RIVER CANYON AND SOUTH GEORGIA COULD PROVE FAVORABLE. THEY INCLUDE HARD CLAYS AND CALCAREOUS SEDIMENTS WITH VARIOUS DE- GREES OF CEMENTATION. IT IS POSSIBLE THAT LAYERS IN THE COASTAL PLAIN THAT WOULD PRESENT DISTINCTLY FAVORABLE SOFT GROUND TUNNELING CONDITIONS COULD BE SELECTED. FOR EXAMPLE, IN COOPER MARL IN CHARLESTON, S.D., TUNNELS 8 FEET IN DIAMETER WERE EXCAVATED BY A LOVATT MACHINE ADVANCING AT THE RATE OF ABOUT 160 FEET IN AN 8 HOUR SHIFT WITHOUT TEMPORARY OR PERMANENT SUPPORT. OBVIOUSLY, EGRESS FOR A DEEP BASE IN THE CONTINENTAL SHELF WOULD REQUIRE SPECIAL FACILITIES, INCLUDING INSTALLING A COM- PRESSED AIR LOCK AND THE LAUNCHING OF MISSILES IN SOME FASHION SIMILAR TO THAT FROM A TRIDENT SUBMARINE. WE, OF COURSE, HAVE NO IDEA IF SUCH AN ARRANGEMENT COULD DEVELOP INTO A PRACTICAL REALITY, BUT AN UNDERWATER HARDENED SITE COULD ELIMINATE MANY OF THE PUBLIC PROBLEMS OF LAND SITES. FIGURE 7
l33 X -4 X I/I 3 SS X 8 u U 3 -a 3 -; 91 O -o c >- u â¢ b T3 u J3 â¢*-! *_Â« IM o -1 o O J( â¢*4 â t â¢ u u a O g > 44 u u â¢ 3 4 o c o e 0) Â«| J< ** 3 > Â£ *H 00 ^4 & fl u O j: â < - V e *^ u o 4 u a. f I 3 U â -i â¢ U Â« e o & -4 H c 1 85^ a Â« 01 u u N 1 I e n - o b 41 - â LJ O " Â« Â« Â« * ^ â - - " I 8 Â« X " u i x u o 3 U w I -* W u w 1 9 91 -â¢ -3 w c u â> 3 u e Â« u x c o â¢J -Â« a - -3 U Â« 3 â s â¢ o Sa -H Â«i n ^ â¢a M 3 - 3. 3. > U O U Â«l CO LU CÂ£.
l34 <r Â£ </l U. uj O O uj â O oe â I/I X LU Q. UJ o o (J o Â§ - ooo! '< 2
l35 I 1
l36 1 O S â¬ 5 O 0) C7I L. 4 jÂ± u Ol â¢"-> <4- 0) â¢Â«- in râ I e 2: Q. Q. a jt i Â£ Cu N tâ at -Â« â¢â â r- +J O 10 <J a ai Â« L . <a 1- râ .O 01 J3 Â«- E T3 01 L. 10 o c u> o a. o 10â<t- \ Sin S sl P" OJ w -a i c Â£7 en
l37 $ o 01 -o O c 01 I I I â¢-, o