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Mechanism and control of ground residual deformation over longwall goaf
GUO Guang-li, WEI Kuang-ling, MU Bin-shan, Gao Jing-xiang, H E Guo-qing
(1. China University of Mining and Technology , Xuzhou 221008 , China ;
2. Chongqing University , Chongqing 400044 , China ;
3. Qiwu Coal Mine , Jining 277606 , China)
Abstract:
The deformation of rupture rock mass in goaf is the main reason for ground terrene residual deformation.Based on field measurement and similar material simulation , the rupture strata structure and its residual deformation characteristics in the longwall goaf and its overburden are pointed out. On the basis of these achievements , the authors propose the mechanism of strengthening rupture rock mass ground and the control measures of deformation resistant structure. Using the case of main coal building in Xinzhuangzi Coal Processing Plant , this paper introduces the influence of strengthening rupture rock mass and deformation resistant structure.
Key words: abandoned goaf ; residual deformation ; rupture rockmass ; deformation mechanism; deformation control
1. INTROD UCTION
The movement and dest ruction of overburden layers caused by underground mining changed overburden engineering geology characteristics and formed the engineering geology condition of extracttion subsidence rupture rock mass ground. Even by long time natural pressure after mining , these phenol mena of residual cavity , bed separation ,mining induced fissure can be seen in goaf and overburden. Subcompaction and gap with saturated water can also be seen in caved goaf . Under the influence of inner and external factors (for example ,ground stress , underground water , superimposed load of new building) , the rupture rock mass will produce second movement and deformation , which is a serious threat to ground buildings safety.This is the main potential safety hazard that restrains large scale application of terrene in abandoned goaf .The deformation of rupture rock mass in goaf is the main reason for residual deformation in collapsed area terrene. Clarifying structure and deformation characteristic of rupture rock mass in goaf , predicting terrene residual subsidence and deformation , adopting suitable measures to strengthen rupture ground and designing reasonable building structure are the basic research directions to guarantee the safety of the buildings above abandoned goaf.
2 RUPTURE ROCK MASS STRUCTURE AND RESID UAL DEFORMATION CHARACTERIS TIC OVER LONGWALL GOAF
After extracting underground ore body , the overburden will move and deform t- hat induces thegreat change of the property and forms of rock ,and will form a new goaf rupture rock mass structure system composed of caving zone , fracture zone and inflection subsidence zone (Fig. 1).
Fig. 1 Rupt ure rock massst ruct ure over longwall goaf
According to a large amount of field inspectionand simulation research results , abandoned goaf’s‘liven up’ and the mechanism of extraction rupture ground unstability can be analyzed as follows :
1) The rupture rock pieces above the edge of longwall goaf articulate with each other and form a construction similar to half arch struct ure with one of its foot t- rending to coal wall. In this structure ,the first and second rupture rocks play key role in the relatively stable structure of rock mass above goaf. If these key rocks lose their stability , they will influence overburden , and produce strata movement and deformation again , then extent toterrene further.
2) The block beam above longwall goaf results in the difference of the crack rockps compactivities in various positions of caving zone. There is unstowed cavity around open off cut , terminal line ,up and down crossheading ( around the edge of goaf). From edge to center of goaf , caving zonecan be divided into sub compaction area , cavingrock accumulated area , caving rock compaction area and full compaction area.
3) In the super critical extraction area above the middle of goaf , caving rupture rock mainly supports vertical pressure stress. It can be compacted by natural pressure as time passing , but since rupture rocks are beyond retrieve , the fissures among rocks will exist forever. It will be compacted again when being suffered additional burden.
4) For the difference of stratum bedded deposit characteristic and each rock formation mechanical property , a large amount of bedded separation fissure will be produced in inflection zone of overburden. Under the influence of underground water and external force , especially vertical burden ,these bed separation fissures may be compactedand closed , which will lead to the subsidence of terrene.Based on the analyses above , we can divide t he“l(fā)iven up ”of rupture rock mass in abandoned goaf into four types :
1) Under the effect of overburden , the rupture rock in goaf body has long term slow creeping deformation.
2) Under the effect of underground water and air , the rupture rock in goaf will be effloresced , its intensity will be attenuated , and the rupture rock can be compacted again under overburden.
3) Since the intensity attenuation of rupture rock and residual coal pillar begin , the overburden above mining dist rict will lose stability again though it is stable before.
4) Under the effect of external forces , the rupture rock mass above mining dist rict will lose structure stability again. The external forces mainly include earth quake force , tectonic stress caused by region geological structure , disturbance stress caused by exploding or mining , addition burden on the surface , etc.
According to the research results of similar material physical analogy and finite element method , under the condition of deep goaf , the residual deformation of terrene is mainly a slow subsidence course and its uneven subsidence is limited , so reinforcing buildingsp ability to resist deformation is the main technological measure to guarantee its safety. Under the influence of external force , the unstability of the secondary block beam or key strata of overburden mass in goaf is the main cause for serious terrene subsidence in shallow goaf . So strengt hening the block beam structure above goaf and key strata , raising the carrying capacity of rock mass balanced structure and increasing the steady of the balanced structure are the main methods to strengthen the rupture ground above abandoned goaf .
3 TREATMENT OF RUPTURE ROCK MASS OF SHALLOW LONGWALL GOAF
Under the influence of external force , the destabilizing of the secondary block rock beam or key strata of overburden is the main cause for serious ground subsidence over shallow goaf . So strengthening t he block beam structure or key strata above goaf and raising its bearing ability and stability are the main ways to control rupture foundation rock mass deformation over abandoned workings. These technological methods mainly include the following six types.
1. Back filling and grouting in whole goaf
The whole goaf and mining induced fissure of overburden should be backfilled completely by cement , tailings , flyash , sand or clay , etc. This method can get rid of a hidden peril of ground subsidence.
2.Grouting concrete column for partial support
Drilling large diameter borehole on the construction field forms the grout cement or reinforced concrete column to provide surface building support . The column must pass through rupture rock body and reach the integrate rock body beeow abandoned mine workings.
3.Grouting to strengthen block beam in fracture zone
Grouting to stow the bed separation and crack fissure in fracture zone can st- rength the compound block beam structure into a whole continuous half arch rock beam over goaf . This measure is suitable for strengt hening ground around goaf border with large cave and sub stowed area. It can prevent half arch block beam above the edge of goaf from losing stability.
4.Grouting to strengthen basement in sagging zone
Grouting to strength basement in sagging zone below the building can integrate rupture rock body into a whole to guarantee the buildings p subsidence uniformity.
5.Accumulating pressure processing
This measure is to prepress the ground by accumulating debris or sand , etc , on the area above abandoned goaf , which will make the potential differential settlement of ground take place , then the ground will be compacted and the intensity will be improved. Moreover the subsidence will reduce in practical project later. This method requests that effective load shouldnpt lighter than additional load caused by new buildings.
6.Using high energy rammer to deal with shallow rupture rock body Using high energy rammer to deal with shallow rupture rock body will compact the fissure and bed separation in shallow ground , and increase the load carrying capacity of shallow ground. This method is mainly suitable for the foundation soilt reatment of general civil buildings constructed on the middle area of goaf .
4 DESIGNING MEASURES OF ANTI2DEFORM ATION STRUCTURE
Under the condition of certain mining deep and even load , longwall goaf seldom produces violent subsidence , and the distribution of residual subsidence is continuous and gradually changed.Buildings above abandoned goaf undoubtedly will be influenced by ground residual deformation. The ground deformation , transiting to the upper structure of building through foundation , will make the structure have additional stress and deformation. Adopting the designing measures to improve the coordination relation among the base , foundation and upper structure is the basic method to protect buildings on goaf. By analyzing the coordinate relation between the ground subsidence and buildingps deformation , we conclude t he following three principles during designing buildings with deformation resistant structure .
1.Structure yielding measures
The technological measures are adopted to absorb part of terrene deformation or to let building have enough flexibility to adapt buildingps unbalanced subsidence and deformation , and to reduce the additional stress caused by terrene deformation. These measures include setting deformation gap , reducing unit length of building or designing flexible building with hinge joint steel frames , which can change the positions related to each other.
2.Structure rigidity strengthening measures
These measures are to raise stiffness and in tegrity of building units to increase their resisting ability of terrene deformation , which include strengt hening stiff ness and intensity of each unitps ground , adding structure components , strengthening component , etc. We can design adjustable base , for example , ground composed of thicker plate or concrete base row. We can also use ram to make the upper structure back to its original position if uneven subsidence happens.
3.Joint structure rigidity strengthening and structure yielding measures
For large scale indust rial buildings , the needs of equip mentinstallation and its technological process must be considered , in order that structure rigidity strength- ening and structure yielding measures can be applied entirely. Under this circumstance , we should use some synthesize methods to meet the needs of p- roduction safety.
5 PROJECT INSTANCE
1.Project general conditions
A main building of a coal dressing plant with crib and bar foundation is 73.5 m long , 35 m wide and about 40 m high. It is a multilayer and multispan reinforced concrete frame structure. This building , with complicated inner structure , has lots of dressing equipment and is sensitive to terreneps unbalanced subsidence and horizontal deformation.
In the west and north below the main building is A1 and A3 coal seam goaf (the relative position of goaf and main building can be seen in Fig.2 ,and this coal mine had been extracted from 1951 to 1962. The extraction depth of seam A3 is 48.8 m ,minable height is 3. 65 m , and the extraction depth of seam A1 is 62 m , minable height is 2.2 m ,stratatilt angle is 22°～25°. Coal mining method is long wall mining on the strike , using breakage method to deal with roof . Reconnoiter research indicated that the rupture rock mass caused by mining develop ment area has reached to the southwest corner of the main building. Its development range is also shown in Fig. 2. The up face of gap development area is only 15 m deep to surface. Around the edge of goaf , there are residual cavities that caused overburden to be seriously damaged and some ground stability to be relatively poor.
Fig. 2 Surface under ground contrast plan near main dressing building
2.Using consolidation grouting to deal with mining rupture rock ground According to the characteristic of mining rupture foundation , the half arch block rock beam structure in cracked zone above goaf can best rengt hened by using consolidation grouting method , which makes the foundation form a integrated , stable half arch rock structure. Designed grouting area is 637 m in this project and the average stage height of grouting is 8 m. In practice ,seven grouting holes have been drilled. The mate rial used in grouting is 425# Portland cement .
3.Measures of designing deformation resistant structure
In order to guarantee dependability of designing , a space finite element model is adopted to analyze the structures with 6 floors and 8 floors of main building. The model analyzed different basis forms , considering inner force and section adjust ment under 10 kinds of combination circumstance ,such as static burden , dynamic burden, earthquake force , the influence of ground deformation and wind burden. The purpose of the analyses is to select the suitable structure stiffness. After many times of analyses and adjust ment , the dist ribution of reinforcement bar was designed. The flexible measurements were used in both units with 8 and 6 floors. Between the two indispensable units , 100 mm deformation fissure has been left .
4.Implementing effect
To verify designing reliability and to ensure safety , the ground subsidence and structure stress were monitored. According to the analyzing of the main building ground subsidence and internal force , we can draw the conclusion that the ground subsidence is even. Basis reactive dist ribution is even and the change of basis reinforces inner force is accorded with normal law. These inform that strengt hening region rupture ground and deformation resistant structure are successful , and these methods guaranteed the main buildingps safety.
6 CONCL USIONS
1) The deformation of rupture rock mass in goaf is the main reason leading to collapse area terrene residual deformation. Under the condition of deep goaf , the major terrene residual deformation is a slow subsidence process , and reinforcing buildingp deformation resistant ability is the main way of potecting its safety.
2) Under the influence of external force , the rupture rock mass losing its st- ructure steadiney is the main reason leading terrene to seriously subsidence deformation in shallow goaf. Strengt hening half arch block beam above the shallow goaf ,increasing the steady and carrying capacity of rupture rock mass ground are the main methods to deal with unstable ground above abandoned goaf .
3) Adopting struct ure rigidity strengt hening and yielding measures to resist deformation ,improving the coordinate deformation relation among buildingps basis , ground and super structure are the basic methods to protect building in goaf safety.
(4) Practical example indicates that the safety of large sized indust rial buildings above shallow goaf can be protected after grouting and using deformation resistant structure.
中文譯文
長壁開采采空區(qū)上部地表殘余變形的機理與控制
摘要：采空區(qū)巖層破裂變形是導(dǎo)致地表殘余變形的主要原因?；诂F(xiàn)場測量和相似材料模擬，采空區(qū)及其上覆巖層巖石斷裂構(gòu)造及殘余變形特性已被揭示。以此為基礎(chǔ)，作者提出了巖層破碎的加強機制和抵抗變形的控制方法。本文將以新莊子煤炭加工廠的主要建筑物為例介紹巖石破碎的影響和抵抗變形的結(jié)構(gòu)。
1.導(dǎo)言
地下開采導(dǎo)致的上覆巖層移動和破壞改變了上覆巖層的工程地質(zhì)特性并形成了開采下沉破裂巖石面的工程學(xué)地質(zhì)情況。即使開采后在長時間自然壓力作用下，采空區(qū)及其上覆巖層中仍能看到殘留空間、地層分離、開采裂縫等現(xiàn)象?？缏涞睦峡諈^(qū)內(nèi)則會出現(xiàn)分段壓實和飽水裂隙。在內(nèi)外因素（如地面應(yīng)力、地下水、新建筑的階層載荷等）的影響下，破碎巖體將產(chǎn)生二次移動和變形，這會對地面建筑的安全形成嚴重威脅。這是抑制廢棄采空區(qū)上土地應(yīng)用的主要安全隱患。塌落區(qū)域地表殘余變形的主要原因是采空區(qū)巖石破碎變形。弄清采空區(qū)巖石破碎結(jié)構(gòu)和變形特性，預(yù)測地表下沉與變形，采取適當措施加固破碎巖層，設(shè)計合理的建筑物結(jié)構(gòu)，是保證采空區(qū)上地面建筑安全的基本研究方向。
1.長壁采空區(qū)上巖石破碎結(jié)構(gòu)與殘余變形特性
地下礦體被開采之后，上覆巖層會移動變形導(dǎo)致巖石性質(zhì)和形態(tài)的強烈變化，并會形成由跨落帶、裂隙帶、彎曲下沉帶組成的新的采空區(qū)巖石破碎結(jié)構(gòu)體系。（圖1）
根據(jù)大量的現(xiàn)場測試和模擬測試結(jié)果，廢棄采空區(qū)的“活躍”和開采破碎區(qū)地面不穩(wěn)定性機制可被分析如下：
1）長壁工作面采空區(qū)邊界上破碎石塊接合在一起形成一種一端伸向煤壁的半拱結(jié)構(gòu)。在這種結(jié)構(gòu)中，首先破裂和二次破裂的巖石對于采空區(qū)上巖體形成相對穩(wěn)定的結(jié)構(gòu)起到了關(guān)鍵作用。如果這些關(guān)鍵巖層失去了穩(wěn)定性，那么將會影響到上覆巖層，導(dǎo)致巖層移動與變形的再次產(chǎn)生，接著進一步影響到表土層。
圖1 長壁開采老空區(qū)上破裂巖石結(jié)構(gòu)
2）采空區(qū)上的石塊條帶造成跨落帶不同位置破裂巖石緊密性的不同。開切眼、停采線和聯(lián)絡(luò)巷（采空區(qū)邊緣）上下都有卸荷空間。從采空區(qū)端部到中部，跨落帶可以分為初級壓緊區(qū)，跨落巖石堆積區(qū)，跨落巖石壓實區(qū)和跨落巖石完全壓實區(qū)。
3）在采空區(qū)中部之上的超臨界開采區(qū)域，跨落巖石主要起支持垂直應(yīng)力的作用。隨著時間的推移，這些破碎巖石可以被自然壓力壓實，但是由于破碎巖石的不可恢復(fù)性，巖石中的裂紋將永久存在。當施加額外載荷后，這些巖石將進一步被壓實。
4）由于巖層存積性質(zhì)的不同和每一巖層的力學(xué)特性，在上覆巖層的彎曲下沉帶產(chǎn)生大量的層狀分離裂縫。在地下水和外力尤其是垂直負荷的作用下，這些巖層分離裂縫將會被壓實閉合，這將導(dǎo)致表土下沉。
綜上所述，我們可將廢棄采空區(qū)上破碎巖體的“活躍”分為四種類型：
1）受上覆巖層影響，采空區(qū)內(nèi)破碎巖體進行長期緩慢的變形。
2）受地下水與空氣的影響，采空區(qū)內(nèi)破碎巖石將被風化，其強度減弱，在上覆載荷下巖石會被進一步壓實。
3）由于破碎巖石強度的衰減和殘留煤柱開始受壓，采區(qū)上覆巖層開始由穩(wěn)定狀態(tài)進入失穩(wěn)狀態(tài)。
4）受外力影響，采空區(qū)上破碎巖石將再次失去結(jié)構(gòu)的穩(wěn)定性。外力主要包括由區(qū)域地質(zhì)結(jié)構(gòu)引起的地震力和構(gòu)造力，爆破或采礦引起的干擾應(yīng)力，附加表土負荷等。
根據(jù)相似材料模擬和有限元方法的研究結(jié)果，在深部采空條件下，表土層的殘余變形主要是緩慢下沉過程，不均勻下沉受到了限制，因此加強建筑物抵抗變形的能力是保證其安全的主要技術(shù)方法。在外力作用下，二次碎石帶或采空區(qū)上關(guān)鍵層巖石失穩(wěn)是淺部采空表土層劇烈下沉的主要原因。因此加固采空區(qū)上碎石帶結(jié)構(gòu)和關(guān)鍵層，提高巖體平衡結(jié)構(gòu)的承載能力和增加平衡結(jié)構(gòu)的穩(wěn)定性是加強廢棄采空區(qū)上地面破裂的主要方法。
3淺部采空破碎巖體的處理
在外力作用下，二次塊狀巖石帶或關(guān)鍵層的不穩(wěn)定是淺部采空上地表劇烈下沉的主要原因。因次加固碎石帶結(jié)構(gòu)或采空區(qū)上關(guān)鍵層，提高其承載能力和穩(wěn)定性是控制廢棄巷道上基巖變形的主要途徑。這些技術(shù)方法主要包括下列六種類型。
1.在整個采空區(qū)充填灌漿
整個采空區(qū)和采礦引起的裂縫應(yīng)該用水泥、礦渣、粉煤灰、沙子或粘土等完全填充。這種方法可以擺脫地表下沉的潛在危險。
2.噴漿凝注局部支護
在建筑地打大鉆孔噴水泥漿或加強混凝土圓柱為表面建筑提供支護。圓柱必須通過破碎巖體到達廢棄礦井巷道下面的完整巖體中。
3.裂隙區(qū)噴漿加固碎石帶
噴漿充填離層和裂隙帶的裂縫可以使碎石帶復(fù)合成為采空區(qū)上一個完整連續(xù)的半拱巖層。這種方法適合接近大面積跨落采空區(qū)邊緣的地面。可以防止采空區(qū)邊緣上半拱形碎石帶失穩(wěn)。
4.噴漿加強彎曲下沉帶基層
噴漿支護建筑物下彎曲下沉帶基層可以整合破碎巖體以保證建筑物均勻下沉。
5.疊壓前處理
這種方法堆積矸石或沙子等先對采空區(qū)上的地面加壓，使地面潛在微沉發(fā)生，然后地面被壓實，強度也得到提高。并且下沉會在以后的實際施工中減小。這種方法要求有效載荷不得小于新建筑的附加載荷。
6.用高能撞錘處理淺部破裂巖體
使用高能撞錘處理淺部巖體能夠壓實淺部地層的裂縫和離層，并能提高淺部地層的承載能力。這種方法主要適用于采空區(qū)中部上普通民用建筑的基土處理。
4抵抗變形建筑物的設(shè)計措施
在一定采高和平均載荷的條件下，長壁開采方法采空區(qū)很少產(chǎn)生劇烈的下沉，殘余下沉的分配是逐漸連續(xù)變化的。廢棄采空區(qū)上的建筑物無疑將受到地表參與變形的影響。穿過地基經(jīng)過建筑物的上部結(jié)構(gòu)的地表變形，會使結(jié)構(gòu)有額外應(yīng)力和變形。采用改善基底、地基與上部建筑物相應(yīng)關(guān)系的設(shè)計措施是保護采空區(qū)上建筑物的基本方法。
通過對地表下沉和建筑物變形相應(yīng)關(guān)系的分析，我們推定出在設(shè)計抵抗變形建筑物中的三個原則如下。
1.建筑物可縮性措施
此方法用于吸收部分表土變形或者使建筑物對不平衡的下沉和變形有足夠的適應(yīng)性，并且減少表土變形引起的額外應(yīng)力。這些措施包括設(shè)置變形孔，減少建筑物的單元長度或者設(shè)計具有鉸接鋼架的撓性建筑，這種結(jié)構(gòu)可以改變彼此的位置。
2.增加建筑物剛度措施
這些措施包括增強每一地面單元的剛性與強度、增加結(jié)構(gòu)成分等，能夠提高建筑物的硬度和完整性以增加其抗變形能力。我們可以設(shè)計可調(diào)整的基底，例如，由厚板塊或者混凝土地基組成的地層。如果出現(xiàn)不均勻的下沉，我們可以使用推車機將上部建筑物推回初始位置。
3.鉸接結(jié)構(gòu)加強剛度和可縮性結(jié)構(gòu)措施
對于大規(guī)模工業(yè)建筑，設(shè)備安置和技術(shù)過程就得詳細安排，以保證加強剛度結(jié)構(gòu)和可縮性結(jié)構(gòu)能被完全應(yīng)用。在這種情況下，應(yīng)采用綜合措施保證建筑物的安全。
5工程實例
1.普通條件下實例
選煤廠中用木垛和棒做地基的主樓是73.5 m長，35 m寬，40 m高。多層，大跨距，鋼筋混凝土結(jié)構(gòu)。這座建筑具有復(fù)雜的內(nèi)部結(jié)構(gòu)，配置很多設(shè)備，并且不能承受不均衡下沉和水平變形。
建筑物的西部和北部是A1、A3煤層采空區(qū)（采空區(qū)和建筑物的相對位置見圖2），該煤礦已于1951年到1962年開采。A3煤層的采深是48.8m，可采高度3.65 m，A1煤層采深62 m，可采高度2.2 m，煤層平均傾角22°～25°。開采方法為走向長壁采煤，跨落法處理頂板?？辈靾蟾嬷赋龅V井開拓導(dǎo)致的巖石破碎已經(jīng)達到主樓的西南角。其開拓范圍也在圖2中表明。開拓區(qū)域的上挖工作面距地表只有15m深。在采空區(qū)邊緣，具有會導(dǎo)致上覆巖層嚴重破壞并使地表穩(wěn)定性受影響的殘余裂空。
2.通過灌漿硬化處理開采破碎巖層
根據(jù)破碎基巖的特性，裂隙帶的半拱形碎石帶可以通過灌漿硬化的方法加固，這使基巖形成一個整體的、穩(wěn)定的半拱巖石結(jié)構(gòu)。此工程中設(shè)計噴漿面積為637平方米，灌漿平均階段高度8m。實際操作中，共打了7個灌漿孔。灌漿使用材料為425#波特蘭水泥。
3.設(shè)計抗變形結(jié)構(gòu)的方法
為保證設(shè)計的可靠性，一種空間有限要素模型被用于分析主樓的6層和8層
結(jié)構(gòu)。模型分析了不同的基礎(chǔ)形式，考慮到內(nèi)力和10種環(huán)境下的階段調(diào)整，如靜態(tài)負荷、動態(tài)負荷、地震力、地面變形影響和風力。分析的目的是選擇合適的剛性結(jié)構(gòu)。經(jīng)過多次的分析和調(diào)整，設(shè)計出了加固棒的分配方法。靈活的測定應(yīng)用
圖2 主樓附近地表與井下對比平面圖
于8層和6層的單元中。在兩個不可或缺的單元中，允許有100 mm的變形裂縫。
4.實施效果
為檢驗設(shè)計可靠性和保證安全，地表變形和結(jié)構(gòu)應(yīng)力都受到監(jiān)測。根據(jù)對主樓地表變形和內(nèi)力的分析，我們得到地表下沉比較平均的結(jié)論。地基作用分布平均，地基加固的內(nèi)力變化與標準規(guī)定一致。這表明加固局部破碎地層和抗變形結(jié)構(gòu)獲得了成功，這些措施保證了主樓的安全。
6.結(jié)論
1）采空區(qū)內(nèi)破碎巖體的變形是導(dǎo)致塌落區(qū)表土殘余變形的主要原因。在深部采空條件下，主要的表土殘余變形是一個緩慢的下沉過程，增強建筑物的抗變形能力是保證其安全的主要途徑。
2）在外力作用下，破碎巖體失去結(jié)構(gòu)平衡是致使淺部采空表土層劇烈下沉變形的主要原因。加強淺部采空區(qū)上的半拱碎石帶，增加破碎巖體的穩(wěn)定性和承載能力是處理廢棄采空區(qū)上不穩(wěn)定巖層的主要方法。
3）采用剛度加強結(jié)構(gòu)和屈服方法抵抗變形，提高建筑物地基、地層和上部構(gòu)造的協(xié)調(diào)變形關(guān)系是保證采空區(qū)上建筑物安全的基本方法。
4）實例表明淺部采空區(qū)上大面積工業(yè)建筑的安全在使用噴漿和抗變形結(jié)構(gòu)后能夠得到保障。