Arch. Min. Sci., Vol. 54 (2009), No 4, p

Ach. Min. Sci., Vol. 54 (2009), No 4, p. 657 670 Electonic vesion (in colo) of this aticle is available: http://mining.achives.pl 657 PIOTR KALISZ* IMPACT OF MINING-INDUCED SURFACE DEFORMATIONS ON REINFORCEMENT OF STRUCTURAL EMBANKMENTS ODDZIAŁYWANIE GÓRNICZYCH DEFORMACJI PODŁOŻA NA ZBROJENIE NASYPÓW BUDOWLANYCH In this pape issues concening the impact of mining exploitation on embankments einfoced with geogids have been discussed, with paticula consideation of oad embankments. Mining defomations cause loosening of subsoil as well as supplementay defomation and geogids stain, which ae built inside embankment stuctue. Moeove, loosening causes changes of subsoil and embankment popeties. Keywods: mining aeas, civil engineeing, embankments, geogids Celem atykułu jest omówienie zagadnień związanych z oddziaływaniem eksploatacji góniczej na zbojenie nasypów budowlanych, wykonane z zastosowaniem geosiatek, ze szczególnym uwzględnieniem nasypów komunikacyjnych. Defomacje pzypowiezchniowej wastwy guntu oddziałują niekozystnie na ziemne budowle nasypowe, zlokalizowane w zasięgu wpływów eksploatacji góniczej. Istotne znaczenie dla ozpatywanego zagadnienia mają głównie odkształcenia poziome ε pzypowiezchniowej wastwy guntu. Odkształcenia powodujące ozluźnianie mają niekozystny wpływ na wytzymałość guntów budujących podłoże i kopusy nasypów ziemnych, powodując twałe zmniejszenie ich spójności. Rozluźnianie niekozystnie oddziałuje też na zbojenie. Zbojenie bezpośedniego podłoża oaz wastw nasypów komunikacyjnych ma na celu popawę ich stateczności oaz wzmocnienie podłoża dóg. Na teenach góniczych zbojenie pzeciwdziała także poziomym odkształceniom ozciągającym, któe powodują ozluźnianie wastw guntu. Geosiatki mogą pacować jedynie na ozciąganie, a zatem nie mogą pzeciwdziałać siłom ściskającym, jakie występują w czasie ujawniania się wpływów eksploatacji w stefie odkształceń ściskających. Oddziaływanie poziomych odkształceń podłoża o chaakteze ozluźniającym na nasypy zbojone powoduje dodatkowe ozciąganie geosiatek. Maksymalna watość dodatkowych sił ozciągających, jakie wystąpią w geosiatkach, wynika z watości odkształceń podłoża i watości sił stycznych między geosiat- * CENTRAL MINING INSTITUTE. DEPARTMENT OF SURFACE AND STRUCTURES PROTECTION. PL. GWARKÓW 1. 40-166 KATOWICE, POLAND

658 ką a guntem poniżej zbojenia. W pacy pzedstawiono zależności, z któych można okeślić watość jednostkowych sił stycznych τ, działających na geosiatki pod wastwą guntu o jednakowej wysokości oaz pod powiezchnią skapy. Na podstawie tych zależności można wyznaczyć odległość, na któej odkształcenia geosiatki osiągną watość odkształceń guntu podłoża. Do obliczeń stateczności skap nasypów w paktyce inżynieskiej stosuje się często metody ównowagi ganicznej, gdzie wskaźnik stateczności okeślany jest na podstawie takich metod, jak metoda Felleniusa czy Bishopa, w któych wpowadzono dodatkowe siły utzymujące od zbojenia. Pzyjmowana do obliczeń stateczności maksymalna siła utzymująca od zbojenia jest ówna sile wynikającej z długotwałej obliczeniowej wytzymałości geosiatki na ozciąganie (LTDS), w założonym okesie użytkowania budowli. Watości sił utzymujących od zbojenia dla nasypów zlokalizowanych na teenach góniczych powinny być zmniejszone ze względu na ozluźnianie podłoża. Można to zealizować pzez wpowadzenie dodatkowego współczynnika zmniejszającego A g pzy obliczaniu wytzymałości długotwałej geosiatek. Na podstawie wstępnych badań wpływu odkształceń podłoża na geosiatki pzyjęto watość tego współczynnika wynoszącą A g = 1,18 dla odkształceń odpowiadających teenom góniczym IV kategoii. Watości współczynnika A g dla teenów góniczych I-IV kategoii mogą być wstępnie pzyjmowane z pzedziału (1,0;1,2. Watość współczynnika zmniejszającego A g powinna być uzależniona od pzewidywanych watości poziomych odkształceń geosiatek, jakie będą wywoływane odkształceniami podłoża budowli ziemnej. Watość ta dla óżnych odzajów geosiatek powinna być okeślona na podstawie odpowiednich badań, któe umożliwią ocenę wpływu dodatkowych odkształceń na ich wytzymałość długotwałą. Należy pzy tym uwzględnić właściwości lepkospężyste geosyntetyków oaz wpływ pełnego cyklu odkształcania podłoża, to jest ozluźniania, a następnie zagęszczania i ponownego ozluźniania, na współpacę geosiatek z wastwami guntu. W obliczeniach stateczności skap nasypów na teenach góniczych należy uwzględniać wpływ poziomych odkształceń ozluźniających na wastwy zbojenia geosyntetycznego oaz na właściwości guntów budujących podłoże i nasypy. Słowa kluczowe: teeny gónicze, budownictwo ziemne, nasypy, geosiatki 1. Intoduction Influence of mining exploitation has a negative impact on eathen stuctues, including stuctual embankments. The above mentioned influence entails both, changes of thei geomety and negative changes of subsoil popeties as well as soil built-in embankments. Changes of teain inclination T, occuing due to mining exploitation, induce in case of oad embankments changes of cosswise and longitudinal inclination of oads and tacks, which can be of pemanent, negative chaacte. Soil subsidence is the cause of changes in gade line of embankments. At pesent, in ode to einfoce subsoil and the main body of eathen stuctues of embankment natue, geosynthetic einfocement, pedominantly in the fom of geogids, is used. Geogids ae also used to constuct oad embankments in mining aeas. The aim of this pape is to discuss issues connected with influence of mining exploitation on embankments and thei einfocement, made with the usage of geogids, with paticula attention paid to oad embankments.

659 2. Impact of mining exploitation on the subsoil and embankments Of a cucial impotance fo the issue in question, i.e. undegound mining exploitation impact on stability of constuctional embankments, have hoizontal defomations ε of uppe layes of subsoil, on which these embankments ae settled. The impact of mining exploitation on oad embankments is pesented schematically in Fig. 1. A) compaction loosening B) R u w max T 0,4 0,4 H R x Fig. 1. Influence of mining exploitation on embankment: A) influence of defomation towads cosswise diection, B) pofile of mining basin slope Displacing undegound exploitation font in the fist phase of defomation in uppe layes of ock mass evokes soil loosening, afte which compacting and subsequent loosening of soil medium occus. Absolute value of soil stain is subjected to decease and afte appopiate eceding of exploitation edge should lowe itself to value ε 0, what, as gound measuements show, does not always ensue fom it (Gustkiewicz et al., 2003). Futhemoe, the eseach (Mika, 1996) has shown, that the soil medium in the last

660 phase of defomation gets into active limit state. In the distance fom constant edges of exploitation, soil is in a state of pemanent defomation. Depending on its location towads these magins it is eithe loosened o compacted. Loosening influences both, popeties and soil stength of soils foming foundations and stuctue of made gound. It also has a negative impact on thei einfocement. Loosening of subsoil may cause tempoay o pemanent loss of subsoil beaing capacity unde eathen stuctues. Due to tempoay loss of subsoil beaing capacity, thee is additional subsidence of a stuctue compaed to suface subsidence caused by mining exploitation beyond each of this stuctue s influence on the subsoil. Loosening causes eduction of hoizontal stess in soil and owing to that loss of its load capacity, which can be egained by soil compaction unde the stuctue due to its weight (Kwiatek, 1997, 2007). Such phenomena have been obseved, among othes, duing the constuction of some high oad embankments of A4 motoway. Pemanent loss of beaing capacity of subsoil is connected with the impact of loosening on stength popeties of soils which fom them. Soil stength, if loosened, is being educed. As fa as non-cohesive soil is concened, decease in value of intenal fiction angle is obseved; howeve, this change is insignificant. Stength eduction of cohesive soil is elated mainly to eduction of cohesion, when intenal fiction angle is slightly educed (Glinko, 1987; Kwiatek, 2007). The cohesion c of cohesive soil is the sum of two components: wate-colloidal c w and stuctual c s. Wate-colloidal cohesion is evesible by natue, and it can be assumed that is does not undego pemanent changes. Howeve, the destuction of fiable stuctual bonds in cohesive soil is pemanent (Glinko, 1987). Reduced soil cohesion value of cohesive soil in mining aeas, may be descibed by elation (Glinko et al., 2002) c c w c s 1 exp( ) k (1) whee: c w wate colloidal cohesion constituent, c s stuctual cohesion constituent, ε value of defomations in soil loosening (avelling) pocess, ε k citical value of defomations in soil loosening pocess, ε k 12.0 mm/m, α coefficient detemined fom expeimental data, 0.1 α 0.3. Citical defomations in the loosening pocess have been detemined on the basis of laboatoy tests (Glinko, 1987) and (Glinko et al., 2002), obtained values fo cohesive soil ae equal to ε k = 9.0 12.0 mm/m. Changes of soil popeties efe also to soil built-in embankments.

In accodance with (Litwinowicz, 1982) educed soil cohesion value can be calculated using the following fomula 661 c R c 0 1 c k (2) c 0 soil cohesion equal to ε = 0, c k soil cohesion equal to ε = ε k, pemanent shea esistance, α coefficient detemined by means of eseach of soil shea stength fo vaious types of soil defomations, e.g. fo clay loam obtained coefficient is equal to 1.5. Assumed to measue stability, beak point paametes fo cohesive soil, foming subsoil and embankments, obtained on the basis of laboatoy tests conducted befoe mining exploitation influence occued, should be educed. Nevetheless, influences of accomplished and foeseen exploitation should be taken into account. Fo defomations in mining aeas of loosening type, at the value geate than o equal to citical value, cohesion should be educed to pemanent shea stength value. 3. Design esistance of geogids Geosynthetics, geogids and geotextiles deployed in ode to einfoce soil, ae made of vaious types of plastics. To the goup of most often used mateials fo thei poduction belong: polypopylene PP, polyethylene PE and polyeste PET, but also polyalcohols, e.g. polyvinyl alcohol PVA, polyamide PA, polyvinids and polycabonates. These mateials ae polymes which eveal viscoelastic popeties, thus in this case, time is of a cucial impotance fo the pocess of thei defomation due to diffeent load values. Studies on popeties of viscoelasticity caied out on geogid samples, made fom polypopylene, high-density polyethylene HDPE and polyestes eveal that state of stess and stain of the samples was influenced by both, stess ate and stess untime (Leshchinsky et al., 1997; Sawicki & Kazimieowicz-Fankowska, 1998; Shinoda & Bathust, 2004). Reseach esults of heological popeties of geosynthetic mateials also show that geogids made of PP and HDPE eveal much bigge ceep and fo the same load in shote time they esult in destuction compaed to geogids made of PET o PVA. Popeties of paticula geosynthetics diffeentiate consideing thei long-tem opeation in the gound in the whole intended peiod of stuctue utilization, which lasts at least seveal dozens yeas. It should be also taken into account in selecting mateial fo embankment einfocement in mining aeas. Quantity chaacteistic of a given geosynthetic is its Ultimate Tensile Stength (UTS), measued in laboatoy tests fo pemanent stain ate fo a shot time peiod. On the basis of this value the Long Tem Design Stength (LTDS), used in engineeing

662 calculations, is denoted, which is measued by using seies of eduction coefficients. These coefficients must also take viscoelastic popeties of polymes into account, in this paticula case, eduction coefficient value is assumed in the limits fom aound 2 to 5 (Leshchinsky et al., 1997; Ajdukiewicz, 2004). Long Tem Design Stength F d is calculated fo the intended peiod of stuctue utilization, in the tempeatue t 30 C and soil eaction 4 ph 12, accoding to the fomula Fk Fd (3) A1 A2 A3 A4 whee: F k the Ultimate Tensile Stength UTS, is detemined fo the constant velocity of samples defomation e.g. in accodance with DIN 10319, it is the value detemined at the confidence level of 95% fo band 1 m width, A 1 coefficient of textile mateial with ceep taken into account, should be detemined pusuant to long-tem eseach, in case when such eseach does not exist fo PP and PE A 1 = 5.00 can be assumed, fo PA and PET A 1 = 2.50, A 2 coefficient of textile mateial allowing fo mechanical defects, mainly duing embankment constuction, fo sandstone A 2 = 1.50, fo gitstones A 2 = 2.00, A 3 taking influence of fastenings (joints) in caying diection into account, in case when such fastenings do not exist A 3 = 1.00, A 4 coefficient of textile mateial, taking influence of gound envionment on a given poduct stength into account, A 4 = 1.00-1.05. γ coefficient of textile mateial, accoding to limit state metod o global facto of safety (Ajdukiewicz & Sobolewski, 1998; Ajdukiewicz, 2004; Kłosek, 2006). Calculated fom the above fomula, value of mateial tensile stength can be applied to embankment dimensioning with long tem load of geosynthetic einfocement taken into account. 4. Impact of mining exploitation on einfocement of embankments Reinfocement of diect subsoil and layes of oad embankments aims to impove its stability and einfoce base laye of oad sufaces. Owning to einfocement, steepness of slopes can be inceased, and at the same time, embankment constuction zone can be naowed. In a longitudinal diection, stength of applied geogids is lowe than thei stength in a cosswise diection, owing to the fact that geneally this diection is stengthened.

663 Eathen stuctues eected in mining aeas, with the use of layes einfoced with geogids, ae subject to additional defomations, foced by undegound mining. Soil defomations ae tansfeed to embankments as a esult of tangential foces occuing unde this embankment. In mining aeas, this einfocement countemeasues against defomations due to hoizontal tensions, which cause loosening of layes of soil. Geogids can only have impact on tension, hence, they cannot counteact compessive foces which take place when impacts of exploitation in the compessive gound defomation zone ae evealed. Impact of loosening of suface layes of the soil on einfoced embankment in a diection pependicula to its long axis is shown schematically in Fig. 2. Impact of hoizontal soil defomation of loosening natue on einfoced embankments leads to supplementay tension in geogids, what negatively affects slope stability. y gs Defomations of geogids equal to soil defomations gs = l x Fig. 2. Example of embankment einfoced with the usage of geogids, subject to influence of subsoil loosening The maximum value of supplementay tension foces, which occu in geogids, esults fom the values of tangential foces between geogid and soil below einfocement. These foces, falling to a band of unitay width, can be obtained fom the geneal equation F = τl (4) whee: τ unit tangent vecto in the aea of whee einfocement with the soil come togethe, l length, at which value of geogid defomation adopts a value of soil defomation (Fig. 2).

664 Value of the unit tangent vecto τ, acting on geogids, depends on the value of soil defomation as well as on vetical load, caused by the weight of supeincumbent layes of soil and suchage load, on type and soil state, and also on a type of geogid. Value of tangent vecto, having an effect on geogids, inceases with the incease of soil defomations, until it eaches bounday value of ε g, above which futhe incease in defomations will not cause incease of thei value. On the basis of peliminay eseach (Kowalczyk & Kalisz, 2003) fo polyeste geogid this value is equal to 5-6 mm/m, at vetical load of 25 kpa and 32.5 kpa. In ode to detemine the value of limiting defomations ε g fo vaious types of geogids, of high and low defomability, at diffeent values of vetical soil load, futhe eseach should be conducted. Value of unit tangent vecto τ, having an effect on geogids unde the laye of soil of the same height, can be expessed by the fomula whee: max (5) g tg C htg (6) max C i 11 ε g bounday defomations of soil unde geogid, fo ε ε g tangent vectos τ = τ max, C i coefficient of soil and geogid inteaction, fo sand value of 0,9 can be assumed (Stilge-Szydło, 2009), (Sieia et al., 2009), σ 11 value of vetical load fom weight of supeincumbent ove the einfocement layes, h total thickness of layes supeincumbent ove geogid, φ angle of intenal fiction of soil in the vicinity of geogid, γ g weight by volume of supeincumbent soil. In a zone unde the slope suface, value of unit tangent vecto τ will be equal to whee: α slope s angle, x length of examined point at the base of slope. i g Ci g xtg tg (7) g Length l, at which value of geogid defomation ε gs eaches value of soil defomation ε, can be obtained fom the elation: unde the laye of the same height l F() C h tg i g g (8)

665 unde the suface of slope at the angle of inclination α l 2F() C tg tg i g g (9) whee: F(ε) value of foce caused by defomation ε in geogid band of unitay width, detemined on the basis of tensile test. Unde embankment slope of the angle of inclination of 45 this length can each to aound 2.0 m fo geogid of value F(ε) based on tension of a sample placed in the gound (Kążelewski & Izbicki, 2004), subjected to soil defomation of value equal to 3.0 mm/m. Fo the same geogid weighted with an embankment 10 m high in a zone beyond the slope, length l will be equal to 0.25 m, and fo geogid built-in at a depth of 1 m this embankment cown will come to aound 2.50 m. These values indicate that defomities of geogids applied fo embankment einfocement elatively quickly assume values of soil defomation ε. Reinfocement of oad embankments educes tansfeing of detimental mining defomations of soil being an effect of loosening on embankment soil, especially in the aeas close to slopes. Soil defomations lead to defomations of geogids, which incease fom 0 to ε at the length l in opposite ends of geogid segment, in a ange of soil defomation impact. Geogid defomities in a elatively shot segment assume values equal to the values of the suface layes defomations, induced by mining exploitation. It esults fom unit tangent vecto τ in a zone whee soil and einfocement come togethe. Loosening of embankment layes situated above einfocement takes place in, being educed alongside with the height, the middle pat of embankment. Subsequent laye of einfocement limits the ange of loosening of layes above it; nonetheless, it equies using a lage numbe of geogids of low defomity, built-in the total width of the embankment. Owing to einfocement, values of defomations caused by mining exploitation in the uppe layes of embankments ae lowe than in soil, what contibutes to potection of oad suface in this diection. Cosswise einfocement of embankment in mining aeas with the usage of geogids only in aeas close to slopes may lead to excessive defomations in the slope zones not subjected to einfocement. In an exteme case, even discontinuous defomations can occu due to the fact that in the soil loosening pocess, einfoced zones ae less pone to defomations than non-einfoced coe embankment aea. Reinfocement of oad embankment in a longitudinal diection to a small extent influences limiting the ange of impact of hoizontal defomations of soil on layes of gound, built-in its stuctue. As fa as linea objects ae concened, longitudinal tension foces in zone of soil loosening ae too stong fo einfocement to counteact them successfully. Theefoe, the embankment cown is, in pinciple, subject to the same hoizontal tension defomations as the suface laye of the gound.

666 5. Evaluation of embankments stability influenced by mining exploitation Calculations of stability slopes and high fill slopes ae done by applying a method of limit equilibium method and numeical methods, with the usage of compute softwae (Cała & Flisiak, 2000), (Cała, 2007). In numeical simulation, influence of mining exploitation on embankments einfoced with geogids is taken into account by setting appopiate bounday conditions (Kowalski, 2006; Kłosek & Szeja, 2008). Evaluation of stability of existing slopes, including slopes in mining aeas, can be also caied out by utilizing inclinometic measuements. In these measuements, shifts in inclinomete holes made in a slope ae egisteed. Values of these shifts ae compaed with values denoted as citical, which, when exceeded, may lead to the loss of slope stability (Domańska & Wichu, 2006; Maschalko et al., 2008). Limit equilibium methods ae often used in engineeing pactice, whee stability facto is povided on the basis of such methods as Fellenius o Bishop s Method (Wiłun, 1987), in which, additional foces holding against einfocement ae implemented. The above mentioned methods belong to so called block methods, whee potential cylindical suface of slip ae assumed, in seach of the lowest value of stability indicato. Solid of a fagment is divided into blocks (bands), consideing thei state of equilibium. Safety (stability) facto F without einfocement is calculated as a quotient of moment of a suppoting foce M U to the moment of otation foces M O M U F (10) In case of slope einfocement thee ae supplementay suppoting foces, whose moment is totalized with suppoting moment, esulting fom foce of intenal fictional esistance and cohesion. Safety facto F can be calculated by means of the fomula M O F M U M M O R M U n Ti 1 M O Y i (11) whee: M R moment suppoting in einfocement, T i foce suppoting fom geogid of a numbe i, Y i geogid distance i fom otation point. Exemplay model of coss-section though a slope einfoced in hoizontal layes of embankments is illustated in Fig. 3. In calculations of stability, it is assumed that supplementay suppoting foces T i fom einfocement wok hoizontally, and thei moments towads the otation point counteact

667 R Y n Y 2 Y 1 T n T 2 X T 1 W = W i Fig. 3. Coss-section though a slope einfoced in a few layes moment M O of gavity foce of blocks (otating foces) (Stilge-Szydło, 2009). In less consevative methods, owing to geogid flexibility, even tangential diection of these foces to cylinde suface aea of a solid of a fagment: is taken into account. It gives highe values of suppoting moments, because fo each laye of einfocement otation am equal to adius R of cylinde suface aea of a fagment lump is assumed. The maximum foce in einfocement, assumed in calculations, is equal to the foce esulting fom the geogid Long Tem Design Stength (LTDS), in the implied peiod of stuctue utilization. It is calculated on the basis of tempoay (shot-tem) stength value of geogid, applying appopiate decease factos (3). Geogid Ultimate Tensile Stength (UTS) fo a band of unitay width is detemined on the basis of laboatoy eseach, conducted in a shot tem, accoding to specified pocedues. In ode to calculate slope stability in mining aeas, fist of all, suppoting foces in einfocement made in the whole embankment width should be accounted fo. At the same time, the influence of hoizontal soil defomation on geogids should be taken into consideation. Requied minimum depth of anchoing L k geogid in soil outside cylinde suface aea of a slip can by calculated accoding to the fomula Ti Lk 2C i n tg (12) whee: T i anchoing foce.

668 Coefficient C i of geogid and suounding soil opeating togethe is detemined on the basis of laboatoy pull-out test, consisting in pulling geogid out fom vetically loaded soil (Moaci & Recalcati, 2006; Moaci & Gioffè, 2006; Sieia et al., 2009). Calculations veifying stability of slopes einfoced geosynthetically with the use of limit equilibium method can be conducted by means of compute pogammes, which seach fo minimal value of safety facto F fo the least disadvantageous axis and slip adius (Ajdukiewicz, 2004). Values of suppoting foces in einfocement of embankments located in mining aeas should be deceased because of soil loosening. It can be ealized fo example by intoducing additional coefficient A g while calculating long-tem stength of geogids, the fomula (3). On the basis of peliminay eseach on influence of soil defomation on geogids (Kowalczyk & Kalisz, 2003) value of this coefficient A g = 1.18 was adopted fo defomations coesponding to mining aeas in categoy IV. This value was allowed fo while evaluating the influence of mining exploitation on embankments of diveways of oad ovepass einfoced with geogids in Jastzębie Zdój. On the basis of pefomed analysis on impacts of mining exploitation, it has been concluded that geogids will be thee subject to supplementay tension due to occuence of defomities with values equal to soil defomations, which each locally to about 1%. On the basis of hitheto expeiments, until pope eseach is conducted, value A g 1.2 can be assumed fo maximum values of defomities, coesponding to mining aeas in categoy IV. Fo smalle defomations, values in a ange of (1.0;1.2) can be peliminay accepted. Value of deceasing facto A g should be dependent on expected values of hoizontal defomations of geogids, which will be caused by soil defomations of eathen stuctue. This value fo vaious types of geogids should be designated on a basis of pope eseach, which will allow fo evaluation of influence of additional stain on thei long-tem stength. Theefoe, viscoelastic popeties of geosynthetics as well as influence of full cycle of soil defomation, that is loosening, and theeafte compacting and anothe loosening, on coopeation of geogids with layes of soil, should be taken into consideation. 6. Conclusions Influence of mining exploitation on embankments einfoced with geogids is displayed mainly by negative impact of hoizontal loosening defomations on mechanical popeties of subsoil and embankment as well as by influence of these defomations on thei einfocement. Loosening defomations in subsoil ae tansfeed to layes of geosynthetic einfocement, tiggeing additional defomations and tensile stess of this einfocement, cucial, because of its opeation in embankment. The aim of geogids is to ensue stability of embankment at the suitable level of secuity, and in mining aeas also potection fom additional, excessive defomations

669 of the uppe sufaces of subsoil and oadways. Thus it is cucial to detemine value of tangential foces, induced by mining exploitation, having an effect on geogids placed in lowe layes of soil. In case of calculating stability of slopes einfoced with geosynthetics by applying limit equilibium method used in engineeing calculations, opeating of supplementay moments of foces suppoting in einfocement is assumed. Values of these foces ae assumed on the basis of long-tem stength of geogids, detemined fo pojected time of utilization of eathen stuctue. Design esistance of the above mentioned stength should also be detemined with impact of defomation caused by hoizontal tension of subsoil, what can be ealized by intoducing additional mateial coefficient. Value of his coefficient should be conditioned on pojected values of mining defomations of soil and type of geogid, what should be a subject of futhe eseach. In calculations of slope stability in mining aeas, impact of hoizontal loosening defomations on both, layes of geosyntethic einfocement and popeties of soil layes foming subsoil and embankments, should be taken into account. Refeences Ajdukiewicz J., 2004. Pojektowanie z geosyntetykami możliwe zagożenia dla pojektantów. Magazyn Autostady n 5/2004. Cała M., 2007. Convex and concave stability analyses with numeical methods. Achives of Mining Sciences, Vol. 52, Issue 1, p. 75-89. Cała M., Flisiak J., 2000. Analiza stateczności skap i zboczy w świetle obliczeń analitycznych i numeycznych. XXIII Zimowa Szkoła Mechaniki Góotwou. Bukowina Tatzańska. Domańska D., Wichu A., 2006. The eseaches on slope stability evaluation with inclinometic measuements. Achives of Mining Sciences, Vol. 51, Issue 4, p. 503-528. Glinko H., Bizoń K., Bizoń T., 2002. Wybane poblemy geotechniki w budownictwie ziemnym na teenach góniczych. Mat. Konf. GIG Poblemy ochony teenów góniczych, Ustoń-Zawodzie. Glinko H., 1987. Pzebieg pocesu ozluźnienia guntów spoistych na teenach góniczych w świetle badań wytzymałościowych i mikostuktualnych. Część II. Metody badań mikostuktuy guntów spoistych i opis zmian ich spójności w pocesie ozluźnienia. Politechnika Lubelska. Gustkiewicz J., Kanciuk A., Stanisławski L., 2003. The infl uence of pauses in longwall woking on suface stains as measued by soil stain measuement devices. Achives of Mining Sciences, Vol. 48, Issue 2, p. 197-218. Kłosek K., 2006. Nawiezchnia i budowle ziemne autostady A-1 w waunkach pognozowanych wpływów podziemnej eksploatacji góniczej. Mateiały XI Konf. Naukowo-Technicznej SITG, Jastzębie-Zdój, s. 123-138. Kłosek K., Szeja K., 2008. Geosyntetyczne wzmocnienia komunikacyjnych budowli ziemnych na teenach góniczych. Badania numeyczne. Mateiały: VII Konfeencja Naukowo-Techniczna: Ochona śodowiska na teenach góniczych, SITG Szczyk, s. 101-112. Kowalczyk A., Kalisz P., 2003. Ocena stateczności skap nasypów najazdowych wiaduktu wzmocnionych geosiatkami w opaciu o badania laboatoyjne z symulacją wpływów góniczych oaz analizę zaistniałych i pognozowanych wpływów góniczych. Paca GIG niepublikowana. Katowice. Kowalski M., 2006. Wpływ pzyjętych waunków bzegowych na odkształcenia modelu podłoża poddanego wpływom defomacji góniczych. Geotechnika i Budownictwo Specjalne. ZSMGiG XXIX, AGH Kaków, s. 657-664. Kążelewski J., Izbicki J.I., 2004. Wybane właściwości eologiczne geosyntetyków. Zimowa Szkoła Mechaniki Góotwou: XXVII Zimowa Szkoła Mechaniki.

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