電(dian)(dian)(dian)力電(dian)(dian)(dian)纜直(zhi)埋敷(fu)設(she)優(you)點:施工快,投資少,一(yi)般(ban)埋深(shen)較淺,一(yi)般(ban)放置于凍土(tu)層以(yi)下,開挖面小,通過綜合考慮電(dian)(dian)(dian)纜埋深(shen)和土(tu)壤熱(re)阻系數,相較于排管方式,電(dian)(dian)(dian)纜載流量較大,同時由于電(dian)(dian)(dian)力電(dian)(dian)(dian)纜敷(fu)設(she)溝(gou)道均已回填,不用考慮因(yin)敷(fu)設(she)在空氣中(zhong)造成的電(dian)(dian)(dian)纜熱(re)脹冷(leng)縮效應,不必采(cai)取蛇形敷(fu)設(she)方式,只需按照(zhao)電(dian)(dian)(dian)纜自身曲度(du)敷(fu)設(she)即(ji)可(ke)。
電(dian)(dian)(dian)(dian)(dian)力(li)電(dian)(dian)(dian)(dian)(dian)纜(lan)直埋敷(fu)(fu)設(she)(she)的(de)缺點:在(zai)我國經濟持續增長(chang)形勢(shi)下,許多城市(shi)不斷擴大,以致原來未在(zai)道路范圍內的(de)直埋電(dian)(dian)(dian)(dian)(dian)纜(lan),隨(sui)著(zhu)市(shi)政建設(she)(she)快速發(fa)展(zhan),時有因機(ji)械施(shi)工被外力(li)損壞,造(zao)成人身傷亡、供(gong)電(dian)(dian)(dian)(dian)(dian)中斷等(deng)事(shi)故。出于供(gong)電(dian)(dian)(dian)(dian)(dian)安全及(ji)可(ke)靠性(xing)考慮(lv),故在(zai)城市(shi)核心區,不建議采用直埋方式敷(fu)(fu)設(she)(she)高(gao)壓(ya)電(dian)(dian)(dian)(dian)(dian)力(li)電(dian)(dian)(dian)(dian)(dian)纜(lan);對(dui)空曠及(ji)未來無(wu)規劃道路的(de)其他地(di)區,可(ke)采用直埋方式敷(fu)(fu)設(she)(she)高(gao)壓(ya)電(dian)(dian)(dian)(dian)(dian)力(li)電(dian)(dian)(dian)(dian)(dian)纜(lan),可(ke)在(zai)一定程度上縮(suo)短施(shi)工周期,降低投(tou)資成本。
直埋電(dian)(dian)纜(lan)敷設方(fang)式多用于同一(yi)通(tong)路少于根的(de)及(ji)以下電(dian)(dian)力電(dian)(dian)纜(lan),在廠區通(tong)往遠距離輔助設施(shi)或城郊(jiao)等不(bu)易有經常性開挖的(de)地段在城鎮(zhen)人行道下較易翻修情況或道路邊緣, 也可用直埋。
廠區內(nei)地下管網較多的地段,可(ke)能有(you)熔化(hua)金屬、高(gao)溫液體溢出的場所,待開發將有(you)較頻繁開挖的地方,不(bu)宜用(yong)直(zhi)埋在化(hua)學腐(fu)蝕或雜散電(dian)(dian)流腐(fu)蝕的土壤范圍,不(bu)得采(cai)用(yong)直(zhi)埋。隨著城市化(hua)進(jin)程不(bu)斷(duan)推(tui)進(jin),大規模(mo)城市改造工程不(bu)斷(duan)增多,同(tong)時(shi)考慮投(tou)入運行后的電(dian)(dian)纜(lan)(lan)運行、維護(hu)和事(shi)故(gu)處(chu)理的及(ji)時(shi)方便,在大城市中電(dian)(dian)纜(lan)(lan)直(zhi)埋敷設方式近(jin)幾(ji)年已逐步不(bu)再提倡采(cai)用(yong)。
排管(guan)敷設(she)優缺(que)點(dian)及(ji)使(shi)用范圍
隨著城(cheng)市(shi)的(de)發(fa)展和工業的(de)增長,電(dian)纜(lan)線路(lu)日益密集,直埋(mai)電(dian)纜(lan)敷設方(fang)式(shi)逐漸被(bei)排管敷設方(fang)式(shi)取代。根(gen)據 DL/T 5221—2005《城(cheng)市(shi)電(dian)力(li)電(dian)纜(lan)線路(lu)設計技術規定》標準中(zhong)的(de)定義(yi),排管敷設方(fang)式(shi)為按規劃(hua)電(dian)纜(lan)根(gen)數開挖壕溝一次(ci)建成多(duo)空管道的(de)地(di)(di)下構(gou)筑物。排管敷設一般適(shi)用(yong)于城(cheng)市(shi)道路(lu)邊(bian)人行道下、電(dian)力(li)電(dian)纜(lan)與各種道路(lu)交叉處、廣場區域(yu)及小區內(nei)電(dian)纜(lan)條數較(jiao)多(duo)、敷設距離較(jiao)長等地(di)(di)段。
電(dian)(dian)(dian)力電(dian)(dian)(dian)纜(lan)(lan)排管(guan)敷(fu)(fu)設的(de)優點:受(shou)(shou)外力破壞影響(xiang)少,能承(cheng)受(shou)(shou)較(jiao)大的(de)荷載(zai),該(gai)敷(fu)(fu)設方式具有(you)施工(gong)工(gong)期短,開挖(wa)面(mian)積較(jiao)小(xiao),占地較(jiao)小(xiao)等優點,而(er)且一般采用階(jie)段式混(hun)凝土包封或全(quan)線包封等措施降低地面(mian)不規則沉降給線路帶來的(de)影響(xiang),在一定程度上對電(dian)(dian)(dian)力電(dian)(dian)(dian)纜(lan)(lan)有(you)一定的(de)保護(hu)性(xing),同時按照規劃電(dian)(dian)(dian)纜(lan)(lan)根數敷(fu)(fu)設空管(guan),一次(ci)成型電(dian)(dian)(dian)纜(lan)(lan)施工(gong)簡單。
電(dian)力(li)電(dian)纜排管(guan)(guan)(guan)敷設的(de)缺點:土建成(cheng)本(ben)高(gao),不(bu)能直接轉彎,散(san)熱(re)條件差。重要的(de)是后期無法擴容的(de)余地,而排管(guan)(guan)(guan)敷設方式大(da)的(de)問題(ti)在于(yu)電(dian)流的(de)損(sun)失,由于(yu)高(gao)壓線路一般采用(yong)單芯電(dian)纜,排管(guan)(guan)(guan)的(de)選材(cai)一般選用(yong)非磁(ci)性管(guan)(guan)(guan)材(cai),現(xian)有較(jiao)常使用(yong)的(de)管(guan)(guan)(guan)材(cai)有電(dian)力(li)專用(yong)氯化聚氯乙烯(PVC-C)管(guan)(guan)(guan)或玻璃纖維纏繞夾砂(sha)管(guan)(guan)(guan)(RPM 管(guan)(guan)(guan))等(deng)非磁(ci)性管(guan)(guan)(guan)材(cai),這種(zhong)管(guan)(guan)(guan)材(cai)可以有效(xiao)的(de)降低(di)環流,節(jie)約(yue)成(cheng)本(ben),但(dan)該種(zhong)管(guan)(guan)(guan)材(cai)主要的(de)制(zhi)約(yue)在于(yu)其對(dui)電(dian)流的(de)損(sun)失。
一般(ban)玻璃(li)纖維纏繞夾砂管(guan)(guan)(RPM 管(guan)(guan))的(de)載流(liu)量校(xiao)正(zheng)系數為0.5-0.7,而(er)氯(lv)化聚(ju)氯(lv)乙烯 (PVC-C) 管(guan)(guan)的(de)載流(liu)量校(xiao)正(zheng)系數僅為0.3-0.5,由于兩種管(guan)(guan)材散熱(re)性差,在地底(di)受(shou)當地地溫及電纜工作溫度影響,電流(liu)損失較大。
雖然現階段,由于投資(zi)及(ji)占地等問題的制約,排管敷(fu)(fu)(fu)設(she)方(fang)式成為城市核心區高壓(ya)電(dian)力電(dian)纜(lan)入地的措施(shi),但從長(chang)遠考慮,受限于一次成型無法擴容(rong)及(ji)電(dian)流損失過(guo)大(da),不建議(yi)使用排管敷(fu)(fu)(fu)設(she)方(fang)式敷(fu)(fu)(fu)設(she)高壓(ya)電(dian)力電(dian)纜(lan)。
電(dian)力電(dian)纜排管一般(ban)用于(yu)地下管網密集的(de)城市道(dao)路(lu)(lu)或挖(wa)掘困難的(de)道(dao)路(lu)(lu)通道(dao);城鎮(zhen)人行道(dao)開挖(wa)不(bu)便且電(dian)纜分期敷設地段;規劃或新建道(dao)路(lu)(lu)地段;易受外力破(po)壞區域;電(dian)纜與(yu)公路(lu)(lu)、鐵路(lu)(lu)等交叉(cha)處;城市道(dao)路(lu)(lu)狹窄且交通繁忙(mang)的(de)地段。