城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)址位(wei)于(yu)(yu)甘肅省(sheng)夏河縣駐地拉卜楞(leng)鎮(zhen)東北(bei)24公里白(bai)石崖南(nan)麓、央曲北(bei)岸(an)。漢代(dai)曾在(zai)此設(she)(she)白(bai)石縣，古(gu)為(wei)軍事(shi)交通(tong)要地。古(gu)八角(jiao)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)為(wei)一(yi)空心十(shi)字(zi)形(xing)(xing)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)。在(zai)十(shi)字(zi)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)各角(jiao)上設(she)(she)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)墩八個(ge)，形(xing)(xing)成八角(jiao)，故名(ming)。古(gu)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)占地20萬平(ping)方米(mi)，城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)墻周長2193米(mi)，墻高達10米(mi)。東西(xi)甕(weng)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)有s形(xing)(xing)通(tong)道。城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)外(wai)有護城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)河。北(bei)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)依山、無門，從西(xi)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)經南(nan)門至(zhi)東城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)筑有外(wai)廓，南(nan)門外(wai)筑有外(wai)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)。城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)墻以沙(sha)土、蘆(lu)葦、紅(hong)柳(liu)等層層夯筑而成。至(zhi)今保存完(wan)好。由(you)于(yu)(yu)墻面多，對(dui)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)下(xia)弩射無死角(jiao)，故易(yi)守難攻。八角(jiao)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)壁壘建筑突破方形(xing)(xing)、矩形(xing)(xing)格(ge)局，式樣(yang)奇特，不(bu)同(tong)于(yu)(yu)一(yi)般(ban)古(gu)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)。據考證，它可能(neng)就是(shi)唐代(dai)雕(diao)窩城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)，宋代(dai)的一(yi)公城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)。
八角(jiao)(jiao)城(cheng)(cheng)故址(zhi)的(de)(de)建(jian)(jian)筑形式，是我國古代城(cheng)(cheng)堡(bao)傳(chuan)統(tong)的(de)(de)建(jian)(jian)筑形式，外掘城(cheng)(cheng)壕，內(nei)建(jian)(jian)城(cheng)(cheng)堡(bao)，引水護城(cheng)(cheng)。城(cheng)(cheng)墻(qiang)為(wei)夯(hang)層(ceng)(ceng)夾棍做法，夾棍粗(cu)細較(jiao)均勻，且排列有(you)序。城(cheng)(cheng)墻(qiang)下部夯(hang)層(ceng)(ceng)較(jiao)厚(hou)(22厘米)，夯(hang)土(tu)層(ceng)(ceng)間有(you)砂石伴有(you)樹(shu)枝。緊(jin)連(lian)內(nei)角(jiao)(jiao)的(de)(de)外角(jiao)(jiao)處(chu)有(you)馬面。
城(cheng)中(zhong)發現了大量的(de)文(wen)物,有唐宋時期的(de)金(jin)屬 貨幣、方磚、條磚、筒瓦(wa)、板瓦(wa)、碓舀、礎石、城(cheng)門樞舀、碾(nian)盤等(deng)。在八角(jiao)(jiao)城(cheng)周圍的(de)平地、丘陵、臺(tai)地上(shang),還保(bao)留 有不少古代棄(qi)耕的(de)梯田(tian),有些梯田(tian)一直修到山頂。八角(jiao)(jiao) 城(cheng)在宋代為黨項、西夏、唃廝啰活動和爭戰的(de)中(zhong)心。
八角(jiao)城(cheng)故址位于夏(xia)(xia)河(he)縣城(cheng)北35公里大(da)(da)夏(xia)(xia)河(he)(古(gu)稱漓(li)(li)水(shui))支(zhi)流央曲河(he)上(shang)游且(qie)隆溝(gou)內臺(tai)地上(shang)，海拔2100米(mi)。出且(qie)隆溝(gou)經(jing)過懷(huai)(huai)羌城(cheng)(即(ji)(ji)麻(ma)當古(gu)城(cheng))、土門(men)關，直(zhi)通(tong)臨夏(xia)(xia)。西邊(bian)是(shi)廣闊的大(da)(da)草原(yuan)，其西北通(tong) 道八角(jiao)城(cheng)故址位于夏(xia)(xia)河(he)縣城(cheng)北35公里大(da)(da)夏(xia)(xia)河(he)(古(gu)稱漓(li)(li)水(shui))支(zhi)流央曲河(he)上(shang)游且(qie)隆溝(gou)內臺(tai)地上(shang)，海拔2100米(mi)。出且(qie)隆溝(gou)經(jing)過懷(huai)(huai)羌城(cheng)(即(ji)(ji)麻(ma)當古(gu)城(cheng))、土門(men)關，直(zhi)通(tong)臨夏(xia)(xia)。西邊(bian)是(shi)廣闊的大(da)(da)草原(yuan)，其西北通(tong)過達里加山隘口，可(ke)直(zhi)通(tong)青海。1981年，甘肅(su)省人民政府公布八角(jiao)城(cheng)故址為省級文物(wu)保護單位。
八角城所在地(di)四周山巒環抱，地(di)層(ceng)屬于巴顏喀喇一一秦嶺地(di)層(ceng)區(qu)北秦嶺地(di)層(ceng)下白(bai)(bai)堊紀，城北是著名的(de)白(bai)(bai)石崖(ya)(ya)。甘加鄉盆地(di)中草(cao)灘(tan)廣闊(kuo)，谷溝寬(kuan)敞(chang)，溪流縱橫(heng)，自古(gu)以來是天然(ran)的(de)優(you)質牧場，盛產甘加羊、牦牛、蕨麻豬等優(you)質品(pin)種。草(cao)甸邊緣(yuan)，巖石裸露(lu)、斷崖(ya)(ya)百丈，形成了橫(heng)亙10余里的(de)白(bai)(bai)石崖(ya)(ya)矗壁，其主(zhu)峰達里加山海拔4636米，為(wei)夏河縣第一高峰。
八角城(cheng)憑(ping)山依水(shui)，居(ju)高臨下，內(nei)城(cheng)外(wai)廓，引水(shui)護城(cheng)，層層設防，首尾相顧。而總體布局又和(he)(he)一(yi)般城(cheng)堡又不相同，特(te)別是(shi)內(nei)城(cheng)20個(ge)面(mian)、16個(ge)外(wai)角(8個(ge)外(wai)直角抹(mo)平后變為16個(ge)外(wai)角)和(he)(he)4個(ge)內(nei)直角相互照應，克服(fu)了(le)一(yi)般城(cheng)堡在防御上不可避免死角的弊(bi)病。是(shi)一(yi)座防御性甚強的城(cheng)堡。北京故宮(gong)外(wai)圍城(cheng)墻的建筑形(xing)制(zhi)與八角城(cheng)的建筑極(ji)為相似。因此，八角城(cheng)故址為研(yan)究(jiu)中國(guo)古代建城(cheng)史具有極(ji)高的藝術(shu)和(he)(he)科研(yan)價值。
八角(jiao)(jiao)城(cheng)(cheng)(cheng)因(yin)其有八個(ge)城(cheng)(cheng)(cheng)角(jiao)(jiao)而得名(ming)，城(cheng)(cheng)(cheng)廓是一個(ge)空(kong)心的十字形。八角(jiao)(jiao)城(cheng)(cheng)(cheng)全長2193.4米，合2.2公(gong)里，城(cheng)(cheng)(cheng)內(nei)占地300畝。城(cheng)(cheng)(cheng)外有護(hu)城(cheng)(cheng)(cheng)河(he)、護(hu)城(cheng)(cheng)(cheng)壕，還有外廓，南門外另有外城(cheng)(cheng)(cheng)。
從建筑工藝(yi)上看(kan)，該城系唐以前(qian)所建，建筑形式上突破了方形格(ge)局，十分獨特。城雖(sui)不小，但城角之(zhi)間(jian)距(ju)離(li)均在(zai)弓弩的有效射(she)程之(zhi)內，可互(hu)為(wei)照(zhao)應，因而(er)易守難攻。
八角(jiao)城(cheng)，藏語稱“卡爾昂”，藏文(wen)史稱為(wei)(wei)“雍仲卡爾”，意為(wei)(wei)“萬字城(cheng)”，實際是(shi)一個空(kong)心(xin)的(de)“十”字形城(cheng)。它打破了(le)傳(chuan)統的(de)方(fang)城(cheng)構筑慣例，內城(cheng)為(wei)(wei)空(kong)心(xin)十字型(xing)，但截(jie)去城(cheng)垣(yuan)四(si)面(mian)凸出部分(fen)的(de)8個角(jiao)，形成為(wei)(wei)20個面(mian)，在“十”字的(de)各角(jiao)上有馬面(mian)，計8個。早(zao)在漢代(dai)，這里就設有白石(shi)縣，《漢書》卷二十八下：金城(cheng)郡轄(xia)縣十三，其中有白石(shi)縣，并有離(li)水(shui)出西塞外，東至袍罕入河。王莽時期稱之為(wei)(wei)頃礫。是(shi)絲(si)綢之路(lu)河南(nan)道上的(de)重要軍事建筑遺(yi)址。
絲綢(chou)之(zhi)路(lu)(lu)(lu)河(he)(he)(he)(he)南道(dao)(dao)(dao)開(kai)創(chuang)于南北朝(chao)時(shi)期，是(shi)由西(xi)域、漠北、涼州(zhou)(zhou)出發(fa)，經(jing)吐(tu)谷(gu)渾(hun)河(he)(he)(he)(he)南國，而(er)往古(gu)代(dai)益州(zhou)(zhou)、建康去的(de)(de)(de)國際通(tong)道(dao)(dao)(dao)。它由許多(duo)(duo)路(lu)(lu)(lu)線(xian)組成，但主要路(lu)(lu)(lu)線(xian)是(shi)：由若羌(qiang)、敦(dun)煌或武威(涼州(zhou)(zhou))出發(fa)，經(jing)過(guo)青海湖至(zhi)黃河(he)(he)(he)(he)以(yi)南的(de)(de)(de)吐(tu)谷(gu)渾(hun)地(di)區，而(er)抵達長江(jiang)上(shang)游的(de)(de)(de)松潘地(di)區，再由松潘地(di)區沿(yan)岷江(jiang)而(er)下至(zhi)成都(dou)。這條路(lu)(lu)(lu)線(xian)在甘(gan)肅省境內(nei)有三(san)段(duan)(duan)：由松潘出發(fa)，沿(yan)東(dong)岷江(jiang)而(er)上(shang)，經(jing)南坪(ping)至(zhi)文縣，這是(shi)陰平南支道(dao)(dao)(dao)；第二段(duan)(duan)是(shi)陰平中支道(dao)(dao)(dao)西(xi)段(duan)(duan)，由文縣出發(fa)，經(jing)峰迭、華嚴諸古(gu)城(cheng)，至(zhi)迭部；第三(san)段(duan)(duan)是(shi)河(he)(he)(he)(he)南中支道(dao)(dao)(dao)，由迭部出發(fa)，經(jing)碌曲、夏河(he)(he)(he)(he)、臨夏，至(zhi)西(xi)寧。這條路(lu)(lu)(lu)線(xian)的(de)(de)(de)沿(yan)線(xian)多(duo)(duo)保(bao)留大量的(de)(de)(de)古(gu)代(dai)城(cheng)址，分(fen)布線(xian)路(lu)(lu)(lu)比(bi)較分(fen)明，由松潘向東(dong)北方向延(yan)伸，多(duo)(duo)半都(dou)是(shi)吐(tu)谷(gu)渾(hun)時(shi)期與唐(tang)(tang)代(dai)的(de)(de)(de)。此次勘察時(shi)，我們在八(ba)角(jiao)城(cheng)內(nei)發(fa)現一些魏晉時(shi)期的(de)(de)(de)殘磚斷(duan)瓦。據當地(di)文物部門的(de)(de)(de)同志講(jiang)，他們曾經(jing)在—八(ba)角(jiao)城(cheng)故址征集到(dao)大量唐(tang)(tang)、宋(song)(song)時(shi)期的(de)(de)(de)金屬貨(huo)(huo)幣，發(fa)現了新莽貨(huo)(huo)幣及其(qi)他文物。因(yin)此，可(ke)初步推測：八(ba)角(jiao)城(cheng)即漢(han)代(dai)的(de)(de)(de)白(bai)石城(cheng)、唐(tang)(tang)代(dai)的(de)(de)(de)雕窩(wo)城(cheng)、宋(song)(song)代(dai)的(de)(de)(de)移公城(cheng)。
由于絲綢(chou)之路河南道(dao)的(de)(de)逐漸(jian)廢棄，又(you)成為唐(tang)蕃古(gu)道(dao)上的(de)(de)重要軍事(shi)設(she)施，因此(ci)，八角城在(zai)唐(tang)、宋時(shi)期，具有雙重身份(fen)：
其一(yi)(yi)，是延續(xu)絲(si)綢之路(lu)河南道的交(jiao)通要道作用(yong)，并(bing)成為(wei)吐(tu)蕃地方政權響廝噦(hui)“聯宋(song)抗夏”、溝通漢藏商路(lu)和(he)在(zai)西(xi)夏截斷河西(xi)走廊絲(si)綢之路(lu)中線后南線上(shang)的重要通道。該城(cheng)(cheng)(cheng)在(zai)唐代(dai)稱“一(yi)(yi)公(gong)城(cheng)(cheng)(cheng)”、“雕窩城(cheng)(cheng)(cheng)”、“葉公(gong)城(cheng)(cheng)(cheng)”。宋(song)崇(chong)寧(ning)二(er)年(nian)改(gai)名為(wei)循化(hua)城(cheng)(cheng)(cheng)。《宋(song)史·地理志》稱：“循化(hua)城(cheng)(cheng)(cheng)， 舊一(yi)(yi)公(gong)城(cheng)(cheng)(cheng)，崇(chong)寧(ning)二(er)年(nian)收(shou)復，改(gai)今名”。“樂(le)州(zhou)。舊邈川城(cheng)(cheng)(cheng)，元符(fu)二(er)年(nian)收(shou)復，建(jian)為(wei)湟州(zhou)，建(jian)中靖(jing)國元年(nian)棄之。崇(chong)寧(ning)二(er)年(nian)又復。三年(nian)，置(zhi)倚郭縣，五年(nian)罷(ba)。大觀三年(nian)，加向德軍節度。宣和(he)元年(nian)，改(gai)為(wei)樂(le)州(zhou)”。
其二，是唐(tang)蕃古(gu)道上(shang)(shang)的重要(yao)軍(jun)事設置，是中央(yang)王朝保護(hu)絲綢之路南線(xian)暢(chang)通和(he)保障郵驛(yi)安全(quan)(quan)的重要(yao)設施。唐(tang)蕃古(gu)道在(zai)甘(gan)(gan)(gan)肅(su)省境(jing)內越過陜(shan)甘(gan)(gan)(gan)兩省界(jie)山——隴山到(dao)達秦州(zhou)(今甘(gan)(gan)(gan)肅(su)天水)，溯(su)渭水繼續(xu)西上(shang)(shang)越鳥鼠山到(dao)臨(lin)州(zhou)(甘(gan)(gan)(gan)肅(su)臨(lin)洮)。從(cong)臨(lin)洮西北行，經(jing)河州(zhou)(甘(gan)(gan)(gan)肅(su)臨(lin)夏)渡黃河進(jin)入青海(hai)境(jing)內，再經(jing)龍支城(青海(hai)民(min)和(he)柴溝北古(gu)城)西北行到(dao)鄯(shan)州(zhou)(青海(hai)樂都)，可以稱古(gu)道東段，全(quan)(quan)在(zai)唐(tang)王朝境(jing)內，這(zhe)是漢代以來從(cong)中原進(jin)入河湟地區的傳統路線(xian)。城內出(chu)土有大量唐(tang)、宋(song)時期的建(jian)筑(zhu)構件和(he)文物。
元、明時期，八角(jiao)城開始廢棄，但(dan)只是一座重要的驛(yi)站。宋(song)代所稱的“移公城”在明代即(ji)青海蒙古(gu)火落赤的駐牧地捏貢川。清代以(yi)來稱甘加川，即(ji)今大夏河的支流鐵龍溝，《中國歷史地圖集·北宋(song)秦鳳路圖》亦(yi)將移公城位置標(biao)示于此一帶。
清(qing)代初年(nian)(nian)(nian)準備在這里開墾屯(tun)田，但由于(yu)自然(ran)條件較差而(er)未能實施。乾隆年(nian)(nian)(nian)間始有“八角城(cheng)”的名(ming)稱，乾隆七年(nian)(nian)(nian)《大(da)學士鄂(e)爾泰為遵旨議(yi)(yi)復(fu)捏貢川(chuan)(chuan)地(di)(di)(di)方屯(tun)田事奏折》：“查(cha)從前鄂(e)彌(mi)達(da)奏請將河州八角城(cheng)之(zhi)捏貢川(chuan)(chuan)地(di)(di)(di)方挑浚(jun)河渠，開墾荒地(di)(di)(di)。臣等議(yi)(yi)令該(gai)督撫委(wei)員查(cha)勘，于(yu)奏到之(zhi)日再議(yi)(yi)。捏貢川(chuan)(chuan)遠在番夷，泉水既不足(zu)以灌田，而(er)地(di)(di)(di)土又難(nan)于(yu)開墾，兼(jian)之(zhi)地(di)(di)(di)寒霜早，不能必其成熟，徒勞民力，虛糜帑項，均屬無益。”清(qing)政府放棄在此地(di)(di)(di)開墾土地(di)(di)(di)的計(ji)劃，說明在清(qing)代時八角城(cheng)已廢棄。
據(ju)當(dang)地一位88歲的藏(zang)(zang)民回憶，清(qing)代末(mo)年(nian)，八角城(cheng)內(nei)尚無居(ju)民居(ju)住(zhu)，城(cheng)內(nei)居(ju)住(zhu)少量(liang)的清(qing)兵。民國時期，當(dang)地漢、藏(zang)(zang)居(ju)民開始(shi)大(da)量(liang)入住(zhu)八角城(cheng)。八角城(cheng)故址內(nei)現有(you)七十余戶人家(jia)，五百多人，藏(zang)(zang)、漢雜(za)居(ju)。藏(zang)(zang)族居(ju)民有(you)三分(fen)之(zhi)二，八角城(cheng)村是附(fu)近地區大(da)的自然村。全村以(yi)放牧為主，略做些農業。村中小學學習藏(zang)(zang)、漢兩種(zhong)語言。
八角(jiao)(jiao)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)故址方位正北(bei)(bei)(bei)，總體上呈北(bei)(bei)(bei)高(gao)南(nan)(nan)(nan)(nan)低，南(nan)(nan)(nan)(nan)北(bei)(bei)(bei)高(gao)差(cha)6米(mi)(mi)(mi)(mi)(mi)(mi)(mi)左(zuo)右(you)(you)；西高(gao)東低，東西高(gao)差(cha)3米(mi)(mi)(mi)(mi)(mi)(mi)(mi)左(zuo)右(you)(you)。整(zheng)個城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)垣保存較好。城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)墻(qiang)(qiang)是由一(yi)(yi)(yi)(yi)層(ceng)土一(yi)(yi)(yi)(yi)層(ceng)砂(sha)石夯筑而(er)成(cheng)。一(yi)(yi)(yi)(yi)般土層(ceng)厚8一(yi)(yi)(yi)(yi)12厘米(mi)(mi)(mi)(mi)(mi)(mi)(mi)，砂(sha)石層(ceng)厚3厘米(mi)(mi)(mi)(mi)(mi)(mi)(mi)左(zuo)右(you)(you)，南(nan)(nan)(nan)(nan)甕(weng)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)及(ji)其他局部地方底(di)部夯層(ceng)厚22厘米(mi)(mi)(mi)(mi)(mi)(mi)(mi)，夾(jia)棍垂直(zhi)距(ju)離42—110厘米(mi)(mi)(mi)(mi)(mi)(mi)(mi)，水平相距(ju)不(bu)(bu)均，夾(jia)棍眼直(zhi)徑為10厘米(mi)(mi)(mi)(mi)(mi)(mi)(mi)左(zuo)右(you)(you)。城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)墻(qiang)(qiang)外(wai)(wai)(wai)圍周長(chang)為2540米(mi)(mi)(mi)(mi)(mi)(mi)(mi)。現存城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)墻(qiang)(qiang)殘高(gao)6米(mi)(mi)(mi)(mi)(mi)(mi)(mi)一(yi)(yi)(yi)(yi)13米(mi)(mi)(mi)(mi)(mi)(mi)(mi)：城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)墻(qiang)(qiang)底(di)寬(kuan)1l米(mi)(mi)(mi)(mi)(mi)(mi)(mi)一(yi)(yi)(yi)(yi)13米(mi)(mi)(mi)(mi)(mi)(mi)(mi)，上寬(kuan)5米(mi)(mi)(mi)(mi)(mi)(mi)(mi)一(yi)(yi)(yi)(yi)18米(mi)(mi)(mi)(mi)(mi)(mi)(mi)。城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)四(si)面(mian)正中有(you)甕(weng)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)。東、西兩面(mian)緊(jin)鄰(lin)甕(weng)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)的(de)南(nan)(nan)(nan)(nan)側各有(you)一(yi)(yi)(yi)(yi)夾(jia)道(dao)，形(xing)(xing)似“S”，東面(mian)夾(jia)道(dao)寬(kuan)5米(mi)(mi)(mi)(mi)(mi)(mi)(mi)(殘)；西面(mian)夾(jia)道(dao)寬(kuan)3米(mi)(mi)(mi)(mi)(mi)(mi)(mi)。整(zheng)個城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)的(de)8個外(wai)(wai)(wai)角(jiao)(jiao)均被(bei)抹平，形(xing)(xing)成(cheng)了16個外(wai)(wai)(wai)角(jiao)(jiao)，內角(jiao)(jiao)為直(zhi)角(jiao)(jiao)，緊(jin)鄰(lin)直(zhi)角(jiao)(jiao)的(de)外(wai)(wai)(wai)角(jiao)(jiao)處(chu)均有(you)一(yi)(yi)(yi)(yi)馬面(mian)，現存馬面(mian)6個。城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)墻(qiang)(qiang)外(wai)(wai)(wai)圍有(you)一(yi)(yi)(yi)(yi)護(hu)(hu)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)壕，護(hu)(hu)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)壕不(bu)(bu)完整(zheng)，殘存部分寬(kuan)4米(mi)(mi)(mi)(mi)(mi)(mi)(mi)一(yi)(yi)(yi)(yi)6米(mi)(mi)(mi)(mi)(mi)(mi)(mi)，深2米(mi)(mi)(mi)(mi)(mi)(mi)(mi)一(yi)(yi)(yi)(yi)6米(mi)(mi)(mi)(mi)(mi)(mi)(mi)，護(hu)(hu)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)壕外(wai)(wai)(wai)有(you)護(hu)(hu)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)河(he)，寬(kuan)6米(mi)(mi)(mi)(mi)(mi)(mi)(mi)一(yi)(yi)(yi)(yi)14米(mi)(mi)(mi)(mi)(mi)(mi)(mi)，深2米(mi)(mi)(mi)(mi)(mi)(mi)(mi)一(yi)(yi)(yi)(yi)13米(mi)(mi)(mi)(mi)(mi)(mi)(mi)，護(hu)(hu)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)河(he)水引自言江(央拉河(he))水，河(he)水從城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)北(bei)(bei)(bei)分兩支流(liu)繞(rao)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)向南(nan)(nan)(nan)(nan)流(liu)，后(hou)匯入(ru)央曲河(he)。護(hu)(hu)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)河(he)外(wai)(wai)(wai)有(you)外(wai)(wai)(wai)廓，外(wai)(wai)(wai)廓輪(lun)廓西、北(bei)(bei)(bei)兩面(mian)較明顯。
八角(jiao)城南面甕城外(wai)(wai)東南角(jiao)有一外(wai)(wai)城，城廓明顯，根據地(di)形(xing)(xing)而建，呈現出(chu)不規則的(de)長方(fang)形(xing)(xing)，長寬為130~66米。從位(wei)置分析(xi)，似是(shi)經(jing)過(guo)此地(di)的(de)商人居住(zhu)之地(di)，相當于今天的(de)旅館(guan)。但有人認(ren)為是(shi)練兵場。
在城內居(ju)(ju)民(min)(min)(min)家(jia)中(zhong)(zhong)發現(xian)的(de)少(shao)量的(de)金屬貨(huo)幣，基本上屬于宋、明(ming)、清(qing)時(shi)(shi)期。同時(shi)(shi)還有(you)元代少(shao)數民(min)(min)(min)族銅(tong)飾牌(pai)和刻有(you)“吳興”銘(ming)文(wen)的(de)銅(tong)牌(pai)，明(ming)代的(de)宣德爐和清(qing)代的(de)酥油燈等。據當(dang)地居(ju)(ju)民(min)(min)(min)講，文(wen)物(wu)販(fan)子經(jing)常出現(xian)在八角城村，居(ju)(ju)民(min)(min)(min)們家(jia)中(zhong)(zhong)的(de)許多(duo)文(wen)物(wu)已經(jing)出售給文(wen)物(wu)販(fan)子。當(dang)地居(ju)(ju)民(min)(min)(min)家(jia)中(zhong)(zhong)還保存大量的(de)灰布(bu)紋瓦、勾頭滴(di)水、吻獸及門枕石等建筑構件(jian)。
根據歷年來(lai)征(zheng)集到的(de)文物以及史料的(de)記(ji)載，八角城(cheng)應(ying)初建于南北朝時期，宋代進行(xing)了完(wan)整的(de)修(xiu)筑(zhu)(zhu)過程，從(cong)筑(zhu)(zhu)城(cheng)的(de)技法(fa)上看，元代也(ye)進行(xing)了較(jiao)大(da)規(gui)模的(de)修(xiu)繕工(gong)程。清代時，八角城(cheng)已被放棄。
秦漢時期(qi)(qi)，甘(gan)(gan)南(nan)(nan)屬于(yu)西(xi)(xi)羌，甘(gan)(gan)加地(di)區因地(di)利位(wei)置(zhi)的(de)(de)特殊，在(zai)此(ci)(ci)設(she)置(zhi)白石縣。甘(gan)(gan)加草原是古代(dai)隴右(you)通(tong)往(wang)青海東南(nan)(nan)部的(de)(de)門戶，八(ba)角(jiao)城(cheng)(cheng)位(wei)居此(ci)(ci)道(dao)的(de)(de)必經之處，而(er)此(ci)(ci)處又成為(wei)東連袍罕(今臨(lin)夏)，西(xi)(xi)通(tong)西(xi)(xi)平 (今樂都)之咽喉要津。北宋(song)(song)時期(qi)(qi)，西(xi)(xi)夏東侵北宋(song)(song)疆土，并切斷河(he)西(xi)(xi)走廊。確廝噦“聯宋(song)(song)抗夏”，開辟了南(nan)(nan)絲(si)綢之路(lu)，并保證了絲(si)綢之路(lu)南(nan)(nan)線(xian)暢(chang)通(tong)無阻。絲(si)綢之路(lu)南(nan)(nan)線(xian)是宋(song)(song)代(dai)通(tong)往(wang)西(xi)(xi)域的(de)(de)通(tong)道(dao)。此(ci)(ci)地(di)地(di)名雖經多次變更(geng)，而(er)各(ge)朝歷代(dai)的(de)(de)高統治者對此(ci)(ci)道(dao)也極(ji)為(wei)重視。因此(ci)(ci)，八(ba)角(jiao)城(cheng)(cheng)在(zai)歷史上溝(gou)通(tong)漢人(ren)與其(qi)他民族關系(xi)、疏通(tong)貿易渠道(dao)及和平友好往(wang)來起到(dao)了積(ji)極(ji)的(de)(de)作用(yong)。
八(ba)角(jiao)(jiao)城(cheng)(cheng)(cheng)故址的(de)建(jian)(jian)筑形(xing)式，是我國古代(dai)城(cheng)(cheng)(cheng)堡(bao)傳統(tong)的(de)建(jian)(jian)筑形(xing)式，外(wai)掘(jue)城(cheng)(cheng)(cheng)壕，內(nei)建(jian)(jian)城(cheng)(cheng)(cheng)堡(bao)，引(yin)水(shui)護城(cheng)(cheng)(cheng)。城(cheng)(cheng)(cheng)墻為(wei)夯(hang)層(ceng)夾棍(gun)(gun)做法，夾棍(gun)(gun)粗細較均勻，且排列有(you)序。城(cheng)(cheng)(cheng)墻下部夯(hang)層(ceng)較厚(22厘米)，夯(hang)土層(ceng)間有(you)砂石伴有(you)樹枝。緊連(lian)內(nei)角(jiao)(jiao)的(de)外(wai)角(jiao)(jiao)處有(you)馬面。八(ba)角(jiao)(jiao)城(cheng)(cheng)(cheng)憑山依水(shui)，居高臨下，內(nei)城(cheng)(cheng)(cheng)外(wai)廓，引(yin)水(shui)護城(cheng)(cheng)(cheng)，層(ceng)層(ceng)設(she)防(fang)(fang)，首尾(wei)相顧(gu)。而總體布(bu)局又和(he)一般城(cheng)(cheng)(cheng)堡(bao)又不相同，特別是內(nei)城(cheng)(cheng)(cheng)20個(ge)(ge)面、16個(ge)(ge)外(wai)角(jiao)(jiao)(8個(ge)(ge)外(wai)直(zhi)角(jiao)(jiao)抹平后變為(wei)16個(ge)(ge)外(wai)角(jiao)(jiao))和(he)4個(ge)(ge)內(nei)直(zhi)角(jiao)(jiao)相互照應，克服了一般城(cheng)(cheng)(cheng)堡(bao)在防(fang)(fang)御上不可避(bi)免(mian)死(si)角(jiao)(jiao)的(de)弊(bi)病。是一座防(fang)(fang)御性(xing)甚強的(de)城(cheng)(cheng)(cheng)堡(bao)。北京(jing)故宮外(wai)圍城(cheng)(cheng)(cheng)墻的(de)建(jian)(jian)筑形(xing)制(zhi)與(yu)八(ba)角(jiao)(jiao)城(cheng)(cheng)(cheng)的(de)建(jian)(jian)筑極為(wei)相似。因此，八(ba)角(jiao)(jiao)城(cheng)(cheng)(cheng)故址為(wei)研(yan)究中國古代(dai)建(jian)(jian)城(cheng)(cheng)(cheng)史(shi)具(ju)有(you)極高的(de)藝術(shu)和(he)科研(yan)價值。
經考古(gu)專家調(diao)查、勘測，所得出的(de)(de)(de)初步結論為，八(ba)(ba)(ba)角城(cheng)(cheng)(cheng)在(zai)(zai)(zai)0.5平方(fang)(fang)公里(li)的(de)(de)(de)范圍內設(she)城(cheng)(cheng)(cheng)建(jian)制，以(yi)其(qi)城(cheng)(cheng)(cheng)為正南北方(fang)(fang)位的(de)(de)(de)中(zhong)軸(zhou)線來(lai)看，已屬我(wo)國古(gu)代(dai)(dai)社會典型的(de)(de)(de)城(cheng)(cheng)(cheng)市風(feng)貌(mao)。城(cheng)(cheng)(cheng)墻下(xia)層整土層常夾有(you)新石(shi)器時(shi)代(dai)(dai)碎陶片，其(qi)上層也有(you)唐(tang)、宋以(yi)來(lai)的(de)(de)(de)陶片出現(xian)，再加上城(cheng)(cheng)(cheng)外西北高地(di)漢墓(mu)群(qun)和出土王莽時(shi)代(dai)(dai)貨幣，推出八(ba)(ba)(ba)角城(cheng)(cheng)(cheng)建(jian)于漢代(dai)(dai)。八(ba)(ba)(ba)角城(cheng)(cheng)(cheng)以(yi)它特有(you)的(de)(de)(de)城(cheng)(cheng)(cheng)垣結構，為我(wo)們展現(xian)了古(gu)代(dai)(dai)屯田點(dian)上設(she)計守防城(cheng)(cheng)(cheng)市的(de)(de)(de)風(feng)貌(mao)，在(zai)(zai)(zai)城(cheng)(cheng)(cheng)堡的(de)(de)(de)設(she)計上突(tu)破過去方(fang)(fang)形(xing)、矩(ju)形(xing)的(de)(de)(de)整框(kuang)框(kuang)而(er)自然體系，在(zai)(zai)(zai)我(wo)國現(xian)存在(zai)(zai)(zai)中(zhong)突(tu)破過去方(fang)(fang)形(xing)、矩(ju)形(xing)的(de)(de)(de)整框(kuang)框(kuang)而(er)自成體系。
我心明亮 
